The impact of structural factors in colon and rectal cancer surgery

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(1)Umeå University Medical Dissertations New Series No 1678, ISSN 0346-6612, ISBN 978-91-7601-147-8 Department of Surgical and Perioperative Sciences Umeå University, SE-901 87 Umeå, Sweden. The impact of structural factors in colon and rectal cancer surgery. Fredrik Brännström. Department of Surgical and Perioperative Sciences Umeå University SE-901 87 Umeå, Sweden.

(2) Copyright© Fredrik Brännström ISBN: 978-91-7601-147-8 ISSN: 0346-6612 Layout: Print & Media Inhouse Printed by: Print & Media Tryckeri Umeå, Sweden 2014.

(3) A journey of a thousand li starts with a single step Lao Zi.

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(5) Abstract The aim of this thesis was to investigate the importance and effect of some key-structural factors on outcome of colorectal cancer surgery. Considerable improvements in the treatment of colorectal cancer, i.e. radiotherapy, chemotherapy and operative technique, have taken place since the beginning of the 80s. Recent years have also seen the introduction of multidisciplinary team (MDT) meetings in routine care, although evidence that this has benefitted treatment selection and outcome is weak. A challenge still remaining, regarding colon cancer surgery, is to improve outcome for the large number of patients presenting as an emergency. Outcome in the emergency situation remains worse in both the short- and long-term perspective compared to elective cases. Although studied extensively, the impact of surgeon’s case-load and degree of specialisation on outcome of surgery remains unclear. The following specific factors were studied: the effect of surgeon’s case-load and degree of specialisation on long-term survival in a well-defined, population- based, and recent cohort; the impact of surgeon’s case-load or degree of specialisation on the number of lymph nodes harvested in routine colon cancer surgery; predictors of preoperative discussion of rectal cancer patients at a MDT conference in Sweden, and whether or not MDT assessment influences decision-making in the treatment of rectal cancer; factors associated with an increased risk for loco-regional recurrence in patients operated as an emergency for colon cancer, in a population-based cohort. Data from the Swedish Colorectal Cancer Register (SCRCR) and the local (Uppsala/Örebro) ROC-register were used to study the effect of surgeon’s caseload and surgeon’s degree of specialisation on long-term survival. Data from six hospitals in the Uppsala/Örebro health care region were extracted for the periods 1995-2006 for rectal cancer, and 1997-2006 for colon cancer. These data were updated with a surgeon-specific number and competence level as well as other missing data. Colon and rectal cancer were analysed separately and each cancer stage was analysed separately (Stages I and II grouped together). Data on patients who had undergone right-sided hemicolectomy were extracted from these data and used to investigate whether the surgeon’s case-load or degree of specialisation had an impact on the number of lymph nodes harvested. For the study on predictors of discussion at a preoperative MDT conference, data on all patients without known metastatic disease at diagnosis, who underwent elective surgery for rectal cancer 2007-2010 in Sweden, were extracted from the SCRCR. For the study on factors associated with preoperative radiotherapy, two groups were extracted from this cohort and analysed separately. The first. V.

(6) group comprised patients who had undergone elective tumour resection with curative intent for pT3c, pT3d, pT4 tumours, and the second comprised patients who had undergone elective tumour resection with curative intent for lymph node-positive tumours. For the study on colon cancer patients operated as an emergency, the local colon cancer registry for the Stockholm-Gotland health care region was used to identify all colon cancer patients subjected to emergency resection with curative intent in this region 1997-2007. Patient records with missing information were updated. The impact of reason for emergency resection, time from admission to surgery, daytime versus night-time operation, ASA score, blood loss, and T- and N-stages on the risk for locoregional recurrence was assessed. When the highest degree of specialisation of surgeons participating in the operation was a non-colorectal surgeon, there was a slightly lower long-term survival for rectal cancer Stages I-II (HR 2.03; 95%CI 1.05-3.92). Apart from this, neither the degree of specialisation nor case-load was associated with better survival. Surgeons with colorectal accreditation were associated with a significantly higher proportion of patients having 12 or more lymph nodes harvested from surgical specimens after right-sided hemicolectomy in both non-adjusted and multivariate analyses, as was also university pathology department. Emergency surgery did not affect the lymph node yield. The number of rectal cancer procedures performed per year at each hospital (hospital volume) was the main predictor of MDT evaluation. Patients treated at hospitals with <29 procedures per year had an odds ratio (OR) for MDT evaluation of 0.15. Tumour stage and age also influenced the chance of MDT evaluation. MDT evaluation significantly predicted the likelihood of being treated with preoperative radiotherapy in patients with pT3c-pT4 tumours (OR 5.06) and lymph node-positive tumours (OR 3.55), even when corrected for co-morbidity and age. The only factor tested, apart from stage, influencing the risk for local recurrence after emergency colon cancer surgery was the indication for emergency surgery; perforations of the colon being a higher risk with a HR of 1.96 (95%CI 1.12-3.43). Case-load and degree of specialisation of the surgeon were found not to be important predictors of outcome in colorectal cancer surgery in this cohort. This suggests that there are other structural-related factors that are more important for outcome in colon and rectal cancer. The degree of specialisation of the surgeon did, however, influence the number of lymph nodes harvested from specimens obtained during routine right-sided colon cancer surgery, which might indicate that a higher degree of specialisation is associated with more extensive surgery. Patients with rectal cancer treated at high-volume hospitals were more likely to be discussed at a MDT conference. This in turn was identified as an independent predictor of treatment with adjuvant radiotherapy. MDT evaluation is thus a structural factor with a potentially greater impact on treatment. VI.

(7) and outcome than surgeon’s caseload and degree of specialisation, at least for patients with rectal cancer. Structural-related risk factors that were expected to predict outcome in emergency colon cancer surgery had no significant influence on the risk for locoregional recurrence.. VII.

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(9) List of Publications Brännström F, Jestin P, Matthiessen P, Gunnarsson U. Surgeon and hospitalrelated risk factors in colorectal cancer surgery. Colorectal Dis 2011;13:1370-5. Brännström F, Jestin P, Matthiessen P, Gunnarsson U. Degree of specialisation of the surgeon influences lymph node yield after right-sided hemicolectomy. Dig Surg 2013;30:362-7. Brännström F, Bjerregaard J, Winbladh A, Nilbert Mef, Revhaug A, Wagenius G, Mörner M. Multidisciplinary Team Conferences Promote Treatment According to Guidelines in Rectal Cancer. Accepted 2014-08-03 Acta Oncologica. Brännström F, Gunnarsson U. Risk factors for local recurrence in emergency resections for colon cancer. Manuscript.. IX.

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(11) Contents Abstract V List of Publications. IX. Contents XI List of Abbreviations. XIII. Introduction 1 Surgeon-related risk factors. 1. Lymph node yield. 2. MDT 3 Emergency surgery. 3. Colorectal cancer registers in Sweden. 4. Accreditation in colorectal surgery Aims of this Thesis The specific aims were: Patients and methods. 5 7 7 9. Study I. 9. Study II. 10. Study III. 11. Study IV. 13. Ethics 14 Results 15 Study I. 15. Study II. 26. Study III. 28. Study IV. 33. Discussion 37 Surgeon’s degree of specialisation, case-load and survival. 37. Surgeon’s degree of specialisation, case-load and lymph node yield. 38. Relevance of differences in lymph node yield. 39. Factors influencing whether or not rectal cancer patients are discussed at a preoperative MDT conference. 39. The association between MDT evaluation and preoperative radiotherapy. 39. Emergency surgery. 40. Gender in Cox proportional hazard models. 41. Case-load 41 Conclusions 41 Future aspects Sammanfattning på Svenska. 42 43. Acknowledgements 45 References 47. XI.

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(13) List of Abbreviations APE AR EMVI Gy HA HR LH MDT MRI OR RH ROC SCRCR TME UH 95% CI. Abdominoperieal resection Anterior resection Extramural vascular invasion Gray (measure of absorbed dose ionizing radiation) Hartmann’s procedure Hazard ratio Local hospital Multidiciplinary team Magnetic resonance imaging Odds ratio Regional hospital Regional oncological centre Swedish Colorectal Cancer Register Total mesorectal excision University Hospital Confidence intervall of 95%. XIII.

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(15) INTRODUCTION. Introduction Colorectal cancer is the second most common cancer among men and women in Sweden. The only curative treatment is surgery, sometimes combined with chemo- or radiotherapy1. A considerable improvement in the treatment of colorectal cancer has taken place since the beginning of the 80s, especially regarding rectal cancer. Rectal cancer was revolutionised when the total mesorectal excision (TME) technique was introduced on a wide basis in the late 1990s2-4. Improvements have also been made in radio- and chemotherapy 5, 6. The introduction of multidisciplinary team (MDT) meetings prior to surgery and postoperatively, for both colon and rectal cancer 7, 8 is another recent change. A challenge that still remains in colon cancer treatment is to improve outcome for the large proportion of patients presenting as an emergency9, 10.. Surgeon-related risk factors Data revealing that outcome of surgery for colorectal cancer was highly dependent on the surgeon began to accumulate in the early 1980s11, 12. Since then, several studies aiming to identify the reasons for this have been performed in order to develop ways of systematically improving surgical treatment for colorectal cancer. The effect of hospital volume is still not clear since results from different studies are contradictory regarding both colon13-17 and rectal cancer surgery16-20. It also remains unclear whether or not high surgeon case-load in colon cancer surgery is associated with better outcome, especially when corrected for hospital volume, 15, 17, 21 . Long-term survival and local recurrence in rectal cancer seem to be better with high case-load surgeons even when correcting for hospital volume18, 22-24 although there are also some contradictory data17, 20. Some studies show better short- as well as long-term outcome in colon as well as in rectal cancer surgery with higher surgeon sub-specialisation17, 23, 25, 26 whereas others have failed to show any significant difference21, 24, 27. However, structured education in TME surgery improves local recurrence rates and cancer-specific mortality28. Most studies examining the effect of surgeon or hospital variables are based on data from the 80s or early 90s14, 15, 18, 19, 22, 25-28, the period when TME was introduced, but prior to the establishment of a wider and deeper experience of that method. It was difficult to predict how the implementation of the TME technique affected the relationship between surgeon-related factors (e.g. case-load, degree of specialisation) and outcome. On the one hand, the TME technique specifies in detail the technical aspects of surgery, which may have widened the gap between good and poor surgery, which in turn may have enhanced the influence of surgeon-related as compared to hospital category-related factors22, 29.. 1.

(16) INTRODUCTION. On the other hand, TME was probably first taken up by highly-specialised surgeons28 which would have provided them with an advantage during the years of introduction. It has previously been shown for colon cancer that the differences in long-term survival between hospital categories have a tendency to decrease with time30. Similar studies on the influence of surgeon’s case-load or degree of specialisation have not yet been performed. The definition of a colorectal surgeon in this kind of study is usually vague and not uniform.. Lymph node yield A higher number of lymph nodes harvested at surgery is associated with better survival for both Stage I-II and Stage III colorectal cancer 31-35. This might be due to stage migration35 or that a higher number of lymph nodes harvested indicates better quality of surgery36-38. Another possibility is a relationship between the number of lymph nodes harvested and a more favourable tumour biology, or unknown patientrelated factors (e.g. immune response)32, 39. University hospital is associated with a higher number of lymph nodes examined in colorectal cancer40, whereas hospital case-load is not40, 41. Pathologists with a higher degree of specialisation are associated with a higher number of nodes assessed33, 36, 38 while the effect of the pathologist case-load is more uncertain36, 38. It has been suggested that high case-load and regular attendance at multidisciplinary meetings are associated with a higher number of lymph nodes assessed after surgery for colorectal cancer36, 38, but that degree of surgeon specialisation is not33. However, it is still uncertain whether this is also true on a population basis and when assessing results from colon cancer surgery alone. It is also uncertain if the surgeon’s case-load or degree of specialisation can be explained by an association between these factors and the category of pathology unit examining the specimens. A much-debated issue in colorectal cancer surgery is the value and risks of proximal vessel ligation in colon cancer surgery. Proximal ligation might yield a higher number of lymph nodes, but at the cost of an increased risk for postoperative complications. Erlangen University Hospital reports 5-year cancer-specific survival of 89% using an extensive surgical technique with careful mesocolic dissection and proximal ligation42. However, the postoperative mortality is 3,1% for elective surgery with a median patient age of 65 years. Arguments have also been raised that dissection in the correct embryonic plane might be of greater importance than proximal vascular ligation43-45.. 2.

(17) INTRODUCTION. MDT MDT conferences are now routine in cancer care, and recommendations agreed upon at these conferences are generally implemented in clinical decision-making, though evidence that this benefits treatment selection and outcome is weak7, 8, 46-50 . The introduction of MDT conferences to routine patient management has had its advantages51-55 but it has also put new demands on resources and may, in some cases, lead to a delay in treatment. It is thus important to evaluate the impact of MDT conferences on treatment-related decision-making and outcome8. Acceptance of the TME technique, refined imaging, careful histopathology evaluation and developments in adjuvant therapy8 have significantly improved the outcome of rectal cancer, with increases in overall survival and disease-free survival, and a reduction in local recurrence rates56-58. This has paralleled the introduction of MDT conferences in clinical practice. The role of MDT conferences has only been addressed in a few studies46-55, 59-61. Preoperative MDT conferences with access to magnetic resonance imaging (MRI) results have been shown to reduce the risk of a positive circumferential resection margin59. Patients discussed at a MDT conference are also more likely to receive neoadjuvant therapy for locally advanced rectal cancers, and to be considered for surgical resection of liver metastases60,61. The National guidelines in Sweden, as in other countries62, state that all patients with rectal cancer should be discussed at a MDT conference. This is not always done, and patient-related as well as structural factors have been suggested to influence the chance of a patient being discussed at a MDT conference.. Emergency surgery In Sweden 21.5% of patients operated for colon cancer are classified as emergency cases63. It is known that these patients have a worse outcome in both the short-64-69 and long-term9,10, 68-71 perspective. The higher postoperative mortality associated with in emergency surgery64-69 seems mainly to be caused by medical complications67. This is probably due to a poorer medical condition caused by the emergency state per se, or to preexisting co-morbidity72 or other habitual adverse factors such as advanced age64, 68, 70, 73. Emergency surgery for colon cancer is associated with stage-specific impaired long-term survival when postoperative mortality is excluded and other tumourspecific risk factors are considered9, 68, 70, 71. It is also associated with a higher risk for local recurrence10. The reason for this is not known, and we still do not know if emergency presentation per se should be a factor to consider when deciding, for example, on adjuvant treatment postoperatively.. 3.

(18) INTRODUCTION. Patients presenting as an emergency are older, have greater co-morbidity and more advanced tumours9, 64, 66, 68, 70, 72, 73. The proportion of patients operated with curative intent is lower among those operated as an emergency than among those operated electively. Furthermore, of patients operated with curative intent, a lower proportion have a radical resection according to the pathology specimen report63, 68, 70. The volume of blood loss during surgery is also greater74.. Colorectal cancer registers in Sweden In Sweden, quality assurance is, by law, the mandatory responsibility of each healthcare provider. An important part of quality control is the National Quality Register. Regional cancer centres administer quality registers for colon and rectal cancer, and are also responsible for regional guidelines regarding colon- and rectal cancer care. It is also mandatory by Swedish law to report all cases of cancer to the National Cancer Register. The completeness of the National Quality Registers for colon and rectal cancer is thus continuously checked against the National Cancer Register, and has been found to be about 98% complete for both registers75, 76. The National Quality Register for rectal cancer started in 1995 and for colon cancer in 2007. In the Uppsala/Örebro Region there is a regional register (ROC register), similar to the nationwide register, that has been running since 1997. This register is also continuously checked against the National Cancer Register and has a completeness exceeding 99%77. These registers have also been validated for key variables78. In the Stockholm/Gotland Region there is a regional register (ROC register), similar to the nationwide register and the ROC register in Uppsala/Örebro and has a completeness exceeding 97%. The ROC register in the Stockholm/Gotland Region has been running since 1996. The National Colon and Rectal Cancer Registers have now been joined to form the Swedish ColoRectal Cancer Register (SCRCR). In these registers, the surgeon performing the main part of the operation is registered as the operating surgeon. It is probable, however, that it is the most experienced surgeon participating in the operation that is responsible for important intraoperative decision-making. The personal identification number, methods and results of staging prior to surgery, date of surgery, type of procedure and other treatments, intra- and postoperative complications, as well as results of the pathology specimen examination are some of the variables covered in the registers. A surgeon-specific identification number is also included in the register and from 2005, a letter indicates the surgeon’s degree of specialisation. Degree of specialisation has four levels: (A), non-specialist (i.e. surgical trainee); (B), specialist in general surgery; (C), specialist in general surgery with at least two years sub-specialisation in colorectal surgery; and (D), accredited colorectal surgeon.. 4.

(19) INTRODUCTION. Accreditation in colorectal surgery European accreditation for colorectal surgery has been in existence for many years, In 1999 a nationwide accreditation board was set up by the Swedish Society for Colorectal Surgery. Swedish accreditation was replaced by the European accreditation in 2007. Both European and the Swedish accreditations are classified as category “D” in the register.. 5.

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(21) AIMS. Aims of this Thesis. The overall aim of this thesis was to investigate the importance and impact of some key structural factors on the outcome of rectal cancer and colon cancer surgery.. The specific aims were: • to identify in a well-defined population-based cohort the impact of surgeon’s case-load and degree of-specialisation on long-term survival, with most of the data being extracted from the time after implementation of the TME concept on a wide basis (Study I) •. to investigate in a well-defined population-based cohort undergoing defined routine colon cancer surgery (right sided hemicolectomy), whether or not the surgeon’s degree of specialisation, or case-load, influences the number of lymph nodes harvested (Study II). •. to identify predictors of discussion at a MDT conference of patients with colorectal cancer (Study III). •. to assess whether or not MDT evaluation influences treatment decisionmaking (Study III). •. to determine, in a population-based cohort, factors associated with increased risk for locoregional recurrence in the group of patients operated for colon cancer as an emergency (Study IV). 7.

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(23) PATIENTS AND METHODS. Patients and methods Study I Patients operated for colorectal cancer at two university hospitals (UH), two regional hospitals (RH) and two local hospitals (LH) in the Uppsala/Örebro health care region were included between 1995 and 2006 for rectal cancer, and 1997-2006 for colon cancer. Each hospital has a defined catchment area and the total number of inhabitants in these catchment areas is approximately 900000. Cases with no resection, local excision, endoscopic polypectomy or where the type of operation was not stated, were excluded. Data from the SCRCR and the ROC-registers were updated with the surgeon-specific number and the letter indicating degree of specialisation where these were missing. The degree of specialisation was judged at each operation and may thus have changed over the period of the study. Data from the registers were collected at the end of 2006. Surgeon’s case-load was calculated as the number of procedures performed as operating surgeon or first or second assistant surgeon. The number of operations was then divided by the total number of years the surgeon had reported to the register. Each patient was categorised according to the operating surgeon’s case-load and also according to the surgeon present with the highest case-load. Patients were divided between a low and a high case-load group according to the median. For some calculations, a second model for analysis was used in which the 4th quartile defined the high case-load group. Patients were also categorised according to the degree of specialisation of the operating surgeon, and according to the degree of specialisation of the surgeon with the highest competence participating in the operation. Furthermore, patients were categorised according to their gender and age at time of surgery. Table 1: Exclusions, Study I Operating surgeon not registered No surgeon registered. Colon. Rectum. 446. 48. 156. 21. Operating surgeon degree of specialisation not registered. 12. 8. No degree of specialisation registered. 12. 8. No survival time registered. 10. 2. 8. . Elective or emergency surgery not registered. A temporary surgeon is not given an individual code number and is therefore excluded. This explains most (400 operations) of the exclusions due to lack of a registered operating surgeon in the colon cancer group.. After exclusion (Table 1), multivariate analysis was performed on data from 1645 rectal cancer patients and 2231 colon cancer patients for assessment of 9.

(24) PATIENTS AND METHODS. the impact of the operating surgeon’s case-load and degree of specialisation. A corresponding analysis for the surgeon with the highest case-load participating in the operation, was made on data from 1671 rectal cancer patients and 2518 colon cancer patients. Temporary surgeons were not assigned an individual code and were thus excluded. Since this explains most of the exclusions in the colon cancer patient group, separate analyses were made where a category “Unknown” experience or degree of specialisation was added to the independent variables degree of specialisation and case-load. A Cox proportional hazard model was used to compare survival in uni- and multivariate analyses. Colon and rectal cancer were analysed separately. Cancer stages were analysed separately (except for Stages I and II that were grouped together). To assess the effect of exclusion due to missing data on surgeon’s degree of specialisation and case-load, all analyses were repeated with the category “unknown” (i.e. data missing) added to the independent variables degree of specialisation and case-load. In the original article division of the different cancer stages into separate analyses was referred to as stratification. Since stratification is also a method used in multivariate analysis, stratified analyses were performed for comparison in this thesis. Statistical analyses were performed using Statistica®software (StatSoft, Tulsa, USA) and STATA®13.1 (StataCorp, Texas, USA).. Study II Data on all 1361 patients who had undergone right-sided hemicolectomy were identified from the study population used in Study I. After exclusion (Figure 1) 821 cases remained for analysis. Patients were divided into groups according to the case-load of the most experienced surgeon participating in the operation. The groups were: very low (0-6.3 operations/year); low (6.4-8.1 operations/ year); medium (8.2-10.0 operations/year); and high (10.1-15.4 operations/year) case-load. Patients were also divided according to the degree of specialisation of the most experienced surgeon participating in the operation, to the patient’s age at the time of surgery, and to the patient’s gender. Operations where the most experienced surgeon was a resident were excluded. Age was divided into below median (<74 years), third quartile (74-81 years) and forth quartile (>81 years). Furthermore, patients were divided according to the category “Pathology department” where RH and LH pathology departments were grouped together since LH send their specimens to a pathology department at a RH. There was no selection by preference between the individual surgeon operating and the individual pathologist examining the specimen at each pathology department. Logistic regression analysis was used to evaluate the odds of harvesting at least 12 lymph nodes.. 10.

(25) PATIENTS AND METHODS. Figure 1: Exclusions, Study II Initially 1361 patients . 198 stage IV and 6 stage unknown. 1157 . 254 with no lymph node data. 903 . 49 with surgeon data missing. 854 . 31 where resident was highest degree of specialisation. 823 . 2 unknown if elective or not. Remaining 821 patients entered. Study III Data on all 6760 patients who underwent elective surgery for rectal cancer between January 2007 and December 2010 in Sweden were extracted from the SCRCR. Patients with metastatic disease at diagnosis and cases with missing data were excluded, leaving 4883 patients for analysis of factors influencing whether or not the patient was discussed at a preoperative MDT conference (Figure 2). MDT discussion was the outcome variable in these analyses. Factors associated with preoperative radiotherapy were studied in patients who had undergone elective tumour resection (anterior resection, abdominoperineal resection or Hartmann’s procedure) with curative intent for pT3c, pT3d, pT4 tumours (n=1043) or for lymph node-positive (pN+) tumours (n=1991) (Figure 2). These analyses were performed separately but with preoperative radiotherapy as outcome variable. This grouping was used since the Swedish national guidelines state that these categories of patients should be treated with preoperative radiotherapy. Valid reasons for not following these guidelines include serious co-morbidity or high age, and these factors were included in the analysis. The intention of these analyses was to assess the impact of MDT discussion on the accuracy of treatment including the effect of MDT assessment on the accuracy of MRI interpretation, and the effect of MDT on the accuracy of the decision. 11.

(26) PATIENTS AND METHODS. Figure 2: Exclusions, Study III Patients without metastasis undergoing elektive surgery Initially 6760 patients in the whole material . 1244 with metastasis and 572 with data on metastasis missing. 4944 . 56 with data on emergency surgery missing. 4888 . 5 with data on MDT missing. Remaining 4883 patients entered Patients with pT3c, pT3c and pT4 tumours Initially 1248 patients with pT3c, pT3d and pT4 tumours . 163 with operaion other than AR, APE or HA. 1085 . 42 with emergency surgery. 1043 . 0 with data on MDT or RT missing. Remaining 1043 patients entered Patients with pN+ tumours Initially 2157 patients with pN1 and pN2 tumours . 122 with operaion other than AR, APE or HA. 2035 . 40 with emergency surgery. 1995 . 4 with data on MDT or RT missing. Remaining 1991 patients entered. 12.

(27) PATIENTS AND METHODS. made based on this interpretation. For this reason pathology stage rather than clinical stage was used in these analyses. Age was divided into quartiles (below median age, third quartile and fourth quartile). Hospital volume, i.e. the number of rectal cancer surgery procedures performed annually, was divided into the quartiles very low-volume (≤114 cases in 4 years), low-volume (115-166 cases in 4 years), medium-volume (167-226 cases in 4 years) and high-volume (above the third quartile, i.e. >226 cases). The Swedish national guidelines state that T1-T2 N0 tumours in the upper and rectum without extramural vascular invasion (EMVI) should not be offered preoperative radiotherapy. Since most of the cT1-2 cN0-staged patients undergoing anterior resection would be assigned to this category, we used this subset of patients (n=500) to evaluate possible over-treatment with preoperative radiotherapy as outcome variable. Proportions were compared using uni- and multivariate logistic regression analysis. Statistical analyses were performed using SPSS© 15.0 (SPSS Inc. Chicago, Illinois, USA).. Study IV All patients with colon cancer who underwent emergency resection in the Stockholm-Gotland Region 1997-2007, where the operation had a curative intent, and was considered radical by the operating surgeon, were included. This Region has 2.2 million inhabitants. Patients where identified using the local colon cancer registry for the Stockholm-Gotland health care region. Patients with the following characteristics were excluded: metachronous/synchronous tumour; patients who were obviously erroneously registered as an emergency case; patients who did not belong to the region; patients who died within 30 days after the operation; patients who had moved from the Region; patients with metastatic disease; and patients who’s notes could not be found (Figure 3): All remaining patient notes were scrutinised for missing relevant information that was added. The endpoint in this study was locoregional recurrence defined as any intra-abdominal recurrence in a non-parenchymal organ, including the retroperitoneum and the abdominal wall. Follow-up was completed 15th of March 2013. Proportions were compared using Pearson’s chi square test. Time from primary surgery until loco-regional recurrence was compared using Cox’s proportional hazard model. Cumulative incidence of locoregional recurrence was calculated using the Kaplan–Meier method. The relationship between volume of blood loss and time of day when the operation was performed was visualised on a scatter plot using a LOWESS regression line made with a bandwidth of 0.8. Statistical analyses were performed using STATA© 13.1 (StataCorp, Texas, USA).. 13.

(28) PATIENTS AND METHODS. Figure 3: Exclusions, Study IV 03 patients with emergency resection for colon cancer 6 where the operation was considered radical and curative by the operating surgeon . 17 patients with synchronous or metachronous tumours. 586 . 30 patients with wrongly marked charts. 556 . 27 patients not belonging to the region. 529 . 47 patients died within 30 days after surgery. 482 . 3 patients moved from the region during the study period. 479 . 9 charts could not be found. 470 7 patients had a metastases. 463 patients entered into the analysis. Ethics Studies I and II were approved by the Regional Ethics Committee in Uppsala (Dnr 2008/162), Study III by the Regional Ethics Committee in Linköping (Dnr 2008/2010/301-31), and Study IV by the Regional Ethics Committee in Stockholm (Dnr 2008/162).. 14.

(29) RESULTS. Results Study I Patients with Stage IV rectal cancer operated by a team where the main surgeon had specialisation level A had a higher mortality risk. Rectal cancer patients operated by a team where the main surgeon had specialisation level B had a higher mortality risk but this difference was only significant in univariate analysis for Stage I-II (Table 2). Patients with rectal cancer not more advanced than Stage I-II, operated by a surgical team with level B as the highest degree of specialisation had a higher mortality risk compared to those operated by a team with higher competence levels (Table 3). Case-load did not affect mortality in any rectal cancer analysis except when all stages were analysed together. Colon cancer operated by a surgical team where the main surgeon had specialisation level B, had a higher mortality risk for Stage III but not for the other stages (Table 4). A patient operated by a surgical team with the highest specialisation level D, had a higher mortality risk in the multivariate analysis including both specialisation and case-load, and an almost significantly higher risk in the analysis including level of specialisation only (Table 5). Stage IV colon cancer patients operated by a team where the main surgeon had a case-load below median showed higher mortality in univariate analysis, and this was also almost significant in the multivariate analysis. Case-load did not affect mortality in any other colon cancer analysis. Age had a considerable impact on mortality risk in all analyses both rectal and colon cancer. Male gender was associated with an increased mortality risk in Stage I-II cancer, and a tendency towards an increased risk in Stage IV rectal cancer. Male gender was associated with an increased mortality risk in Stages I-III colon cancer. For rectal cancer there were no significant differences in the results when adding the category “Unknown” to the independent variables “Surgeon’s degree of specialisation” and “Surgeon’s case-load”. Neither did the cases with unknown data per se differ significantly from the reference category.. 15.

(30) 16. . Case-load. Low. High. Age. Median or younger. Older than median. Gender. Female. Male. Specialisation level. A. B. C. D. Case-load. Low. . . . . . . . . . STAGE 3. . . . . . . . Median or younger. Older than median. . . 2.09. 1.00. 1.00. High. Age. . . 0.93. . 1.06. 1.00. 1.31. 2.48. . 1.33. 1.00. . 2.57. 1.00. . 1.00. 1.07. 1.13. 1.00. C. D. 1.60. . B. . 0.79. . A. . . STAGE 1-2 Specialisation level. 1.64-2.66. REF. REF. 0.73-1.18. 0.82-1.36. REF. 0.81-2.13. 0.79-7.81. . 1.05-1.71. REF. 2.00-3.31. REF. REF. 0.85-1.36. 0.87-1.48. REF. 1.10-2.31. 0.25-2.47. . 95% CI. <0.001. . . . 0.530. . 0.650. . 0.272. 0.121. . 0.021. . . <0.001. . . . 0.555. . 0.348. . 0.014. 0.679. . p-value. Univatiate analysis . HR. . . . Table 2: Main surgeon, rectal cancer. 2.08. 1.00. 1.04. 1.00. 0.98. 1.92. . 1.35. 1.00. 2.54. 1.00. . 1.12. 1.00. 1.45. 0.97. . 1.62-2.66. REF. 0.81-1.34. REF. 0.60-1.59. 0.61-6.09. . 1.05-1.73. REF. 1.98-3.28. REF. 0.86-1.46. REF. 1.00-2.11. 0.31-3.07. . 95% CI. <0.001. 0.759. 0.922. 0.263. . 0.017. <0.001. 0.409. 0.051. 0.964. . p-value. Multivariate analysis I HR. 2.08. 1.00. . 1.00. 0.98. . . . . . . 1.35. 1.00. . 2.01. 1.00. . 1.00. 1.10. . . . . . . 1.63-2.65. REF. REF. 0.77-1.24. . 1.05-1.73. REF. 3.34. REF. REF. 0.87-1.40. . 95% CI. <0.001. . 0.852. . . . . . 0.017. <0.001. 0.420. . p-value. Multivariate analysis II HR. 2.08. 1.00. 1.00. 0.97. 1.04. 1.00. 0.98. 1.94. 1.35. 1.00. . 2.55. 1.00. . 1.00. 1.10. . 1.15. 1.00. 1.42. 0.93. . 1.62-2.67. REF. REF. 0.75-1.27. 0.79-1.36. REF. 0.60-1.61. 0.61-6.17. 1.05-1.73. REF. 1.98-3.29. REF. REF. 0.85-1.42. 0.87-1.52. REF. 0.97-2.07. 0.30-2.96. . 95% CI. <0.001. . . . 0.839. . 0.795. . 0.943. 0.260. . 0.017. . . <0.001. . . . 0.469. . 0.319. . 0.070. 0.908. . p-value. Multivariate analysis III HR. RESULTS.

(31) 1.13. . Male. Specialisation level. A. B. C. D. Case-load. . STAGE 4. . . . . . . Female. . . Age. Median or younger. Older than median. Gender. Female. Male. . . . . . . 0.98-1.83. REF. 1.00-1.85. REF. REF. 0.68-1.26. 0.81-1.56. REF. 0.80-3.18. 1.36-8.50. 0.87-1.42. REF. . 0.066. . . 0.051. . . . 0.625. . 0.474. . 0.188. 0.009. . 0.373. . 1.35. 1.00. 1.48. 1.00. 1.10. 1.00. 1.51. 3.84. 1.08. 1.00. 0.99-1.87. REF. 1.08-2.03. REF. 0.80-1.53. REF. 0.75-3.07. 1.52-9.72. 0.85-1.39. REF. 0.062. 0.015. 0.549. 0.251. 0.004. 0.519. . 1.40. 1.00. . 1.42. 1.00. . 1.00. 0.92. . . . . . . 1.09. 1.00. 1.02-1.92. REF. 1.04-1.94. REF. REF. 0.68-1.26. . 0.85-1.39. REF. 0.037. . 0.028. . 0.604. . . . . . 0.514. . 1.35. 1.00. 1.49. 1.00. 1.00. 0.85. 1.04. 1.00. 1.59. 4.13. 1.09. 1.00. 0.98-1.87. REF. 1.09-2.04. REF. REF. 0.60-1.20. 0.73-1.48. REF. 0.78-3.26. 1.61-10.58. 0.85-1.40. REF. . 0.064. . . 0.013. . . . 0.361. . 0.818. . 0.204. 0.003. . 0.504. . The effect of different levels of specialisation and case-load of the main surgeon on long-term survival in rectal cancer surgery. Low case-load means that the main surgeon of the operation has a lower than median case-load. Multivariate analysis I includes the variables specialisation level, age and gender but not case-load. Multivariate analysis II includes the variables case-load, age and gender but not specialisation level. Multivariate analysis III includes all variables (specialisation level, case-load, age and gender).. 1.34. 1.00. . 1.36. 1.00. 1.00. 0.93. Low. High. . . 1.00. 1.59. 3.40. . 1.12. 1.00. Gender. . RESULTS. 17.

(32) 18. Low. . High. Age. Median or younger. Older than median. Gender. Female. Male. . . . . . . Low. . Case-load. . B. . . Specialisation level. STAGE 3. C. Male. . D. Female. . . Gender. . . Median or younger. Older than median. . . High. Case-load. . Age. D. . . C. . . B. . 1.14. 1.00. . 2.12. 1.00. . 1.00. 0.96. . 0.97. 1.00. 1.10. . 1.30. 1.00. . 2.50. 1.00. . 1.00. 1.06. . 1.08. 1.00. 2.50. . STAGE 1-2 Specialisation level. 0.89-1.45. REF. 1.66-2.69. REF. REF. 0.76-1.22. 0.75-1.26. REF. 0.55-2.19. . 1.01-1.66. REF. 1.94-3.21. REF. REF. 0.84-1.35. 0.83-1.40. REF. 1.30-4.79. . 95% CI. 0.296. . . <0.001. . . . 0.745. . 0.820. . 0.784. . 0.039. . . <0.001. . . . 0.581. . 0.536. . 0.006. . p-value. Univatiate analysis . HR. . . . 1.10. 1.00. 2.12. 1.00. 1.03. 1.00. 0.87. . 1.32. 1.00. 2.47. 1.00. . 1.05. 1.00. 2.04. . HR. 0.86-1.41. REF. 1.66-2.71. REF. 0.80-1.34. REF. 0.44-1.74. . 1.04-1.70. REF. 1.92-3.17. REF. 0.82-1.36. REF. 1.06-3.92. . 95% CI. 0.444. <0.001. 0.802. 0.699. . 0.025. 0.698. 0.698. 0.032. . p-value. Multivariate analysis I. Table 3: Most experienced surgeon participating in the operation, rectal cancer.. 1.10. 1.00. . 2.13. 1.00. . 1.00. 0.90. . . . . . 1.32. 1.00. . 2.50. 1.00. . 1.00. 1.05. . . . . . 0.86-1.40. REF. 1.67-2.71. REF. REF. 0.71-1.14. . 1.03-1.69. REF. 1.95-3.22. REF. REF. 0.83-1.33. . 95% CI. 0.446. . <0.001. . 0.389. . . . . 0.027. <0.001. 0.694. . p-value. Multivariate analysis II HR. 1.11. 1.00. 2.14. 1.00. 1.00. 0.92. 1.02. 1.00. 0.90. 1.33. 1.00. . 2.46. 1.00. . 1.00. 1.02. . 1.05. 1.00. 2.02. . 0.86-1.41. REF. 1.68-2.74. REF. REF. 0.72-1.17. 0.78-1.33. REF. 0.45-1.82. 1.04-1.70. REF. 1.91-3.17. REF. REF. 0.80-1.30. 0.82-1.36. REF. 1.05-3.92. . 95% CI. 0.424. . . <0.001. . . . 0.482. . 0.883. . 0.775. . 0.025. . . <0.001. . . . 0.866. . 0.687. . 0.036. . p-value. Multivariate analysis III HR. RESULTS.

(33) Case-load. Low. High. Age. Median or younger. Older than median. Gender. Female. Male. . . . . . . . . . . 1.31. 1.00. . 1.39. 1.00. . 1.00. 0.87. . 1.06. 1.00. 0.96-1.78. REF. 1.02-1.89. REF. REF. 0.63-1.19. 0.77-1.47. REF. 2.00 0.27-14.53. . 0.092. . . 0.035. . . . 0.374. . 0.718. . 0.495. 1.35. 1.00. 1.44. 1.00. 1.03. 1.00. 1.41. 0.99-1.86. REF. 1.05-1.96. REF. 0.74-1.43. REF. 0.19-10.40. 0.060. 0.022. 0.846. 0.736. 1.37. 1.00. . 1.48. 1.00. . 1.00. 0.82. . . . . . 1.00-1.87. REF. 1.08-2.03. REF. REF. 0.59-1.12. . 0.050. . 0.014. . 0.213. . . . . 1.37. 1.00. 1.48. 1.00. 1.00. 0.81. 0.98. 1.00. 1.53. 1.00-1.87. REF. 1.08-2.02. REF. REF. 0.58-1.13. 0.70-1.38. REF. 0.21-11.37. . 0.053. . . 0.015. . . . 0.207. . 0.923. . 0.676. The effect of different levels of specialisation and case-load of the surgeon with the highest degree of specialisation level and highest case-load participating in the operation on long-term survival in rectal cancer surgery. Low case-load means that the surgeon with the highest case-load participating in the operation has a lower than median case-load. Multivariate analysis I includes the variables specialisation level, age and gender but not case-load. Multivariate analysis II includes the variables case-load, age and gender but not specialisation level. Multivariate analysis III includes all variables (specialisation level, case-load, age and gender).. C. D. . B. . . Specialisation level. STAGE 4. RESULTS. 19.

(34) 20. STAGE 3. . 1.18. 1.00. High. D. Low. 1.02. C. Case-load. 1.37. 1.00. B. . 1.14. A. 2.23. Emergency. Specialisation level. 1.00. Elective. REF. 0.96-1.44. 0.76-1.38. REF. 1.06-1.78. 0.86-1.51. . 1.75-2.86. REF. 1.08-1.64. . 1.33. Operation. Male. REF. . 1.00. Female. 2..62-4.20. REF. REF. 0.82-1.25. Gender. 3.31. Older than median. Age. 1.00. . High. Median or younger. 1.01. 1.00. Low. . 1.35. Case-load. REF. 1.00. C. D. 0.99-1.84. 1.24. 0.69-1.23 0.96-1.62. 0.92. . B. . 95% CI. . 0.115. . 0.872. . 0.018. 0.365. . <0.001. . . 0.007. . . <0.001. . . . 0.896. . 0.054. . 0.103. 0.571. . p-value. Univatiate analysis . HR. A. STAGE 1-2 Specialisation level. . Table 4: Main surgeon, colon cancer.. 0.93. 1.00. 1.33. 1.12. . 2.03. 1.00. 1.45. 1.00. 3.42. 1.00. 1.23. 1.00. 1.13. 0.85. . 0.69-1.25. REF. 1.02-1.73. 0.85-1.49. . 1.59-2.60. REF. 1.18-1.80. REF. 2.70-4.35. REF. 0.90-1.67. REF. 0.87-1.47. 0.63-1.14. . 95% CI. 0.621. . 0.033. 0.418. . <0.001. <0.001. <0.001. 0.192. 0.368. 0.277. . p-value. Multivariate analysis I HR. 1.00. 1.19. . . . . . . 2.09. 1.00. . 1.47. 1.00. . 3.40. 1.00. . 1.00. 1.00. . . . . . . REF. 0.97-1.47. . 1.63-2.67. REF. 1.20-1.82. REF. 2.68-4.31. REF. REF. 0.81-1.23. . 95% CI. . 0.088. . . . . . . <0.001. . . <0.001. . . <0.001. . . . 0.997. . . . . . . p-value. Multivariate analysis II HR. 1.00. 1.08. 0.93. 1.00. 1.28. 1.07. . 1.96. 1.00. 1.47. 1.00. 3.52. 1.00. 1.00. 1.14. 1.27. 1.00. 1.07. 0.79. . REF. 0.84-1.40. 0.69-1.26. REF. 0.95-1.72. 0.76-1.49. . 1.71-2.25. REF. 1.19-1.82. REF. 2.77-4.48. REF. REF. 0.87-1.49. 0.93-1.73. REF. 0.80-1.44. 0.56-1.11. . 95% CI. . 0.550. . 0.643. . 0.104. 0.710. . <0.001. . . <0.001. . . <0.001. . . . 0.332. . 0.138. . 0.646. 0.173. . p-value. Multivariate analysis III HR. RESULTS.

(35) 1.20. Emergency. 0.94-1.53. REF. . 1.00. 0.81-1.27. 1.01. Male. Operation. Elective. REF. 1.00. Female. 1.18-1.89. . 1.49. REF. REF. 1.01-1.60. 0.62-1.16. REF. 0.84-1.53. 0.83-1.63. 1.24-1.92. REF. Gender. Older than median. . 1.00. 1.00. High. Age. Median or younger. 1.27. Low. . 0.85. D. Case-load. 1.13. 1.00. C. 1.16. A. B. . 1.54. Specialisation level. Emergency. . Operation. 1.07-1.61. REF. 1.77-2.68. REF. . 0.153. . . 0.915. . . 0.001. . . . 0.038. . 0.304. . 0.412. 0.387. . <0.001. . . 0.009. . . <0.001. . 1.16. 1.00. . 1.06. 1.00. . 1.45. 1.00. . . . . 0.86. 1.00. 1.09. 1.16. . 1.67. 1.00. 1.36. 1.00. 2.20. 1.00. 0.90-1.49. REF. 0.90-1.49. REF. 1.15-1.84. REF. 0.63-1.17. REF. 0.80-1.47. 0.82-1.62. . 1.34-2.08. REF. 1.11-1.67. REF. 1.79-2.72. REF. 0.261. . . 0.637. . . 0.002. . . . . . 0.339. . 0.597. 0.405. . <0.001. 0.003. <0.001. . 1.15. 1.00. . 1.05. 1.00. . 1.46. 1.00. . 1.00. 1.25. . . . . . . 1.62. 1.00. . 1.34. 1.00. . 2.23. 1.00. 0.89-1.48. REF. 0.83-1.32. REF. 1.16-1.85. REF. REF. 1.00-1.58. 1.30-2.01. REF. 1.10-1.65. REF. 1.80-2.74. REF. . 0.283. . . 0.697. . . 0.001. . . . 0.053. . . . . . . <0.001. . . <0.005. . . <0.001. . 1.15. 1.00. 1.05. 1.00. 1.46. 1.00. 1.00. 1.22. 0.90. 1.00. 0.97. 1.00. 1.66. 1.00. 1.36. 1.00. 2.20. 1.00. 0.89-1.48. REF. 0.83-1.33. REF. 1.15-1.85. REF. REF. 0.89-1.68. 0.65-1.23. REF. 0.68-1.38. 0.67-1.50. 1.33-2.07. REF. 1.07-1.67. REF. 1.80-2.72. REF. . 0.273. . . 0.687. . . 0.002. . . . 0.220. . 0.499. . 0.857. 0.992. . <0.001. . . 0.003. . . <0.001. . The effect of different levels of specialisation and case-load of the main surgeon on long-term survival in colon cancer surgery. Low case-load means that the main surgeon of the operation has a lower than median case-load. Multivariate analysis I includes the variables specialisation level, age and gender but not case-load. Multivariate analysis II includes the variables case-load, age and gender but not specialisation level. Multivariate analysis III includes all variables (specialisation level, case-load, age and gender).. STAGE 4. 1.31. Male. 1.00. 1.00. Female. Elective. . 2.17. Gender. Older than median. . 1.00. Median or younger. Age. RESULTS. 21.

(36) 22. STAGE 3. 1.25. Male. 1.00. High. . 1.07. Low. Case-load. 0.86. D. REF. 0.88-1.31. 0.67-1.09. REF. 0.98-1.66. 1.27. 1.00. B. 0.66-2.51. . 1.72-2.74. REF. 1.02-1.52. REF. 2.59-4.04. REF. REF. 0.88-1.31. 1.28. C. A. . 2.17. Emergency. Specialisation level. 1.00. Elective. . 1.00. Female. Operation. . 3.23. Older than median. Gender. 1.00. Median or younger. . 1.00. High. Age. 1.07. Low. . 1.22. Case-load. REF. 1.00. C. D. 0.98-1.53. 0.99-1.70. 1.30. B. 0.50-2.27. . 1.07. . 95% CI. . 0.485. . 0.213. . 0.070. 0.467. . <0.001. . . 0.028. . . <0.001. . . . 0.475. . 0.082. . 0.058. 0.866. . p-value. Univatiate analysis. HR. A. STAGE 1-2 Specialisation level. . 0.83. 1.00. 1.12. 0.91. . 2.04. 1.00. 1.30. 1.00. 3.28. 1.00. 1.25. 1.00. 1.15. 1.06. . HR. 0.66-1.04. REF. 0.86-1.47. 0.47-1.80. . 1.61-2.58. REF. 1.06-1.59. REF. 2.62-4.10. REF. 1.00-1.57. REF. 0.87-1.50. 0.50-2.27. . 95% CI. 0.106. 0.106. 0.794. . <0.001. 0.009. <0.001. 0.051. 0.323. 0.880. . p-value. Multivariate analysis I. Table 5: Most experienced surgeon participating in the operation, colon cancer.. 1.00. 1.02. . . . . . . 2.05. 1.00. . 1.32. 1.00. . 3.26. 1.00. . 1.00. 0.99. . . . . . . REF. 0.84-1.25. . 1.62-2.60. REF. 1.09-1.61. REF. 2.61-4.07. REF. REF. 0.82-1.21. . 95% CI. . 0.835. . . . . . . <0.001. . . 0.005. . . <0.001. . . . 0.952. . . . . . . p-value. Multivariate analysis II HR. 1.00. 0.95. 0.82. 1.00. 1.15. 0.94. . 2.04. 1.00. 1.32. 1.00. 3.34. 1.00. 1.00. 1.04. 1.28. 1.00. 1.14. 1.06. . REF. 0.76-1.18. 0.65-1.04. REF. 0.87-1.52. 0.47-1.85. . 1.61-2.58. REF. 1.08-1.61. REF. 2.67-4.18. REF. REF. 0.83-1.29. 1.01-1.61. REF. 0.86-1.51. 0.49-2.28. . 95% CI. . 0.630. . 0.097. . 0.334. 0.849. . <0.001. . . 0.006. . . <0.001. . . . 0.748. . 0.040. . 0.365. 0.883. . p-value. Multivariate analysis III HR. RESULTS.

(37) . 1.00. 1.18. Elective. Emergency. . 0.98. Male. Operation. . 1.00. Gender. 1.47. Female. 1.00. . Median or younger. 1.00. High. Age. Older than median. 1.11. Low. D. . 0.83. C. Case-load. 1.05. 1.00. B. 0.97. Specialisation level. A. 0.93-1.51. REF. 0.79-1.22. REF. 1.19-1.84. REF. REF. 0.89-1.37. 0.65-1.06. REF. 0.78-1.42. 0.36-2.62. . 0.162. . . 0.859. . . <0.001. . . . 0.368. . 0.138. . 0.760. 0.950. 1.14. 1.00. 1.02. 1.00. 1.45. 1.00. 0.85. 1.00. 1.00. 1.02. 1.64. 1.00. 1.36. 1.00. 2.14. 1.00. 0.89-1.46. REF. 0.82-1.28. REF. 1.16-1.81. REF. 0.66-1.08. REF. 0.74-1.36. 0.37-2.77. 1.32-2.03. REF. 1.12-1.66. REF. 1.74-2.62. REF. 0.289. 0.842. 0.001. 0.188. 0.976. 0.975. <0.001. 0.002. <0.001. . 1.15. 1.00. . 1.01. 1.00. . 1.46. 1.00. . 1.00. 1.07. . . . . . . 1.63. 1.00. . 1.34. 1.00. . 2.15. 1.00. 0.90-1.47. REF. 0.81-1.26. REF. 1.17-1.82. REF. REF. 0.86-1.33. 1.31-2.02. REF. 1.10-1.64. REF. 1.76-2.64. REF. . 0.264. . . 0.931. . . 0.001. . . . 0.529. . . . . . . <0.001. . . 0.003. . . <0.001. . 1.14. 1.00. 1.02. 1.00. 1.46. 1.00. 1.00. 1.04. 0.85. 1.00. 0.99. 0.99. 1.64. 1.00. 1.36. 1.00. 2.13. 1.00. 0.89-1.46. REF. 0.82-1.28. REF. 1.17-1.82. REF. REF. 0.81-1.32. 0.66-1.09. REF. 0.72-1.36. 0.36-2.73. 1.32-2.04. REF. 1.12-1.66. REF. 1.74-2.62. REF. . 0.302. . . 0.832. . . <0.001. . . . 0.778. . 0.193. . 0.928. 0.989. . <0.001. . . 0.002. . . <0.001. . The effect of different levels of specialisation and case-load of the surgeon with the highest degree of specialisation level and highest case-load participating in the operation on long-term survival in colon cancer surgery. Low case-load means that the surgeon with the highest case-load participating in the surgery has a lower than median case-load. Multivariate analysis I includes the variables specialisation level, age and gender but not case-load. Multivariate analysis II includes the variables caseload, age and gender but not specialisation level. Multivariate analysis III includes all variables (specialisation level, case-load, age and gender).. STAGE 4. <0.001. . REF. 1.57. 1.27-1.94. 1.00. 0.006. Elective. 1.09-1.61. . . <0.001. Emergency. 1.32. Male. REF. . . 1.00. Female. 1.72-2.58. REF. . . Gender. Operation. 2.11. Older than median. . 1.00. Age. Median or younger. RESULTS. 23.

(38) RESULTS. When the category “Unknown” was added to the independent variables “Surgeon’s degree of specialisation” and “Surgeon’s case-load” in the analysis on colon cancer, a few minor differences were seen. A patient with Stage I-II operated by a team where the main surgeon had specialisation level B, had in this analysis a higher mortality risk (HR 1.30; CI95% 1.02-1.66; p-value 0.037). In the multivariate model including degree of specialisation but without compensation for case-load, the impact on mortality risk of a team where the main surgeon had specialisation level B was no longer significant for Stage III (HR 1.26; CI95% 0.98-1.61; p-value 0.070). A patient operated by a surgical team where highest level of specialisation was level B, had in this analysis a higher mortality risk for Stage I-II (HR 1.36; CI95% 1.05-1.74; p-value 0.018) and for Stage III (HR 1.29; CI95% 1.01-1.65; p-value 0.042). The higher mortality risk for patients operated by a team where highest level of specialisation was level D was no longer significant in the multivariate analysis (HR 1.25; CI95% 0.99-1.57; p-value 0.058). In the analysis on colon cancer, cases with unknown data did differ significantly from the reference category in a few instances. The cases with unknown data on the degree of specialisation of the main surgeon differed from the reference category in the univariate analysis for Stage I-II (HR 4.56; CI95% 1.45-14.40; p-value 0.010). The cases with unknown data on the surgeon with the highest specialisation differed from the reference category in the univariate analysis for Stage I-II (HR 4.72; CI95% 1.50-14.84; p-value 0.008). The cases with unknown data on the surgeon with the highest case-load, differed from the reference category in the univariate analysis for Stage I-II (HR 1.72; CI95% 1.16-2.56; pvalue 0.007), in the univariate analysis for Stage IV (HR 1.72; CI95% 1.61-2.38; p-value 0.018) and in the multivariate analysis that did not compensate for surgeon specialisation for Stage IV (HR 1.54; CI95% 1.03-2.29; p-value 0.035). Median case-load was 9 operations per year (range 0-18) for rectal cancer and 8 operations per year (0-15) for colon cancer. In the stratified analysis, there was a barely significant increase in mortality for patients operated by a team where the operating surgeon had specialisation level A or B, but there was no difference when comparing teams according to the highest degree of specialisation participating in the operation (Table 6). 24.

(39) . . . Elective. Emergency. . 1.08-1.47. 1.26. Operation. Male. REF. 1.00. Female. 1.75-2.37. . 2.04. REF. REF. 0.83-1.15. Gender. Older than median. . Age. 1.00. 1.00. High. Median or younger. 0.97. Low. . 1.08. Case-load. REF. 1.00. C. D. 0.91-1.28. 1.02-1.75. 1.33. B. 1.01-3.41. 95% CI. 1.86. . Specialisation level. . 0.003. <0.001. 0.759. 0.387. 0.037. 0.045. . . . 1.25. 1.00. . 2.05. 1.00. . 1.00. 0.92. . 1.02. 1.00. 1.42. . . HR. . 1.07-1.45. REF. 1.76-2.38. REF. REF. 0.79-1.07. 0.87-1.20. REF. 0.91-2.22. 95% CI. . . . <0.001. . . <0.001. . . . 0.286. . 0.819. . 0.125. . . p-value. Most experienced surgeon. Rectal cancer . p-value. Main surgeon. A. HR. . . . Table 6: Multivariate analyses stratified by tumour stage. 1.96. 1.00. 1.29. 1.00. 2.21. 1.00. 1.00. 1.13. 1.02. 1.00. 1.11. 0.94. HR. 1.71-2.25. REF. 1.14-1.47. REF. 1.95-2.51. REF. REF. 0.97-1.33. 0.85-1.22. REF. 0.92-1.32. 0.77-1.16. 95% CI. <0.001. . . <0.001. . . <0.001. . . . 0.121. . 0.853. . 0.270. 0.565. . p-value. Main surgeon. 1.58. 1.00. 1.25. 1.00. 2.16. 1.00. 1.00. 0.99. 0.97. 1.00. 1.11. 1.04. HR. 1.37-1.80. REF. 1.11-1.41. REF. 1.92-2.44. REF. REF. 0.87-1.13. 0.85-1.11. REF. 0.94-1.32. 0.66-1.64. 95% CI. <0.001. . . <0.001. . . <0.001. . . . 0.864. . 0.658. . 0.226. 0.855. . p-value. Most experienced surgeon. Colon cancer . RESULTS. 25.

(40) RESULTS. Study II The mean number of lymph nodes harvested was 11.1. The largest discrepancy (2.0 nodes) was seen between non-colorectal surgeons and accredited colorectal surgeons, while the smallest discrepancy (0.4 nodes) was seen comparing elective and emergency operations (Table 7). Table 7: Number of lymph nodes harvested in right sided hemicolectomy. . . All cases. . N. Mean Median Range. Interquartile range. 821. 11.1. 10. 1-33. 7-14. Specialisation of surgeon Non-colorectal. 149. 9.6. 9. 1-26. 6-13. . Special interest. 389. 11.2. 10. 1-33. 6-15. Accredited. 283. 11.6. 11. 1-32. 8-15 6-14. Case-load of surgeon. Very low. 205. 10.3. 9. 1-26. . Low. 224. 11.0. 10. 1-31. 7-14. . Medium. 230. 11.3. 11. 1-32. 7-14. . High. 162. 11.8. 11. 1-33. 7-15. Pathology department. University. 335. 12.0. 11. 1-33. 7-15. . Non-university. 486. 11.5. 10. 1-32. 6-13.25. Type of operation. Elective. 714. 11.1. 10. 1-33. 7-14. . Emergency. 107. 10.7. 10. 2-25. 6-15. Patient age. < 74yr. 370. 11.9. 11. 1-32. 8-15. . 74-81yr. 215. 10.6. 10. 1-32. 6-14. . > 81yr. 236. 10.2. 9. 1-33. 6-13. Stage. I - II. 525. 10.6. 10. 1-32. 6-14. . III. 296. 11.9. 11. 1-33. 8-15. Patient gender. Man. 354. 10.7. 10. 1-32. 6-14. . Woman. 467. 11.3. 11. 1-33. 7-15. Number of lymph nodes harvested during right-sided hemicolectomy in the 821 patients remaining after exclusion of patients with missing data. Special interest = a surgeon with at least two years subspecialisation in colorectal surgery but without colorectal accreditation.. The odds of having at least 12 nodes assessed in the non-adjusted analyses was higher for surgeons with a special interest in colorectal surgery, surgeons with colorectal accreditation, university pathology departments, patients older than 74 years, and patients with Stage III cancer (Table 8). Results were comparable in the multivariate analyses, except for surgeons with a special interest in colorectal surgery, where the odds ratio was similar but no longer significant (Table 8).. 26.

(41) 133 134. Special interest Accredited Very low Low. . . Case-load of surgeon. Non-university. 74-81yr > 81yr I and II III Man Woman. . Stage. . Patient gender. . 266. 220. 155. 331. 153. 141. 192. N. 201. 134. 141. 194. 83. 74. 178. 45. 290. 172. 163. 77. 96. 90. 72. 133. 158. 44. 335. ≥12 nodes. 1.00. 0.81. 1.55. 1.00. 0.59. 0.57. 1.00. 1.06. 1.00. 1.00. 1.73. 1.26. 1.00. 0.94. 0.76. 2.12. 1.62. 1.00. OR. Crude. REF. 0.61-1.07. 1.16-2.07. REF. 0.42-0.82. 0.40-0.57. REF. 0.70-1.60. REF. REF. 1.30-2.30. 0.84-1.90. REF. 0.65-1.36. 0.51-1.11. 1.39-3.23. 1.09-2.45. REF. CI 95%. . 0.134. 0.003. 0.002. 0.001. . 0.777. . <0.001. 0.256. 0.735. 0.157. 0.001. 0.018. . p-value. 1.00. 0.84. 1.57. 1.00. 0.59. 0.57. 1.00. 1.02. 1.00. 1.00. 1.73. 1.46. 1.00. 1.22. 1.37. 1.95. 1.45. 1.00. . OR. Adjusted. REF. 0.60-1.08. 1.16-2.13. REF. 0.42-0.84. 0.40-0.81. REF. 0.66-1.59. REF. REF. 1.26-2.38. 0.95-2.27. REF. 0.82-1.81. 0,84-2.23. 1.16-3.26. 0.91-2.32. REF. CI 95%. . 0.143. 0.003. . 0.003. 0.002. . 0.914. . . 0.001. 0.087. . 0.329. 0.210. 0.015. 0.122. . . p-value. Results from the unadjusted and multivariate logistic regression models on the 821 patients remaining after exclusion. The lowest tolerance statistic was 0.355.. < 74yr. 62. . 424. Elective Emergency. Patient age. Type of operation. 172 314. University. Pathology dept. 85. High. . 134. Medium. . 150. 231. 105. 486. Non-colorectal. All Patients. <12 nodes. Specialisation of surgeon. . . Table 8: Odds of having at least 12 lymph nodes examined. Right sided hemicolectomy.. RESULTS. 27.

(42) RESULTS. The pathology department category influenced the risk for lymph node yield not being registered, with university hospitals having 28% missing data compared to 17% for non-university hospitals (OR 1.92; 95%CI 1.43-2.51). No other variable influenced the risk for lymph node yield not being registered. Study III Of all patients who underwent elective surgery for rectal cancer 2007-2010 in Sweden, 78% were discussed at a preoperative MDT conference. Preoperative staging was complete in 96% of patients discussed at a preoperative MDT compared to 63% of patients who were not evaluated at a MDT conference. Patients treated at a low-volume hospital (29-42 rectal cancer operations annually) and very low-volume hospital (<29 rectal cancer surgeries annually) were considerably less likely to be discussed at a MDT conference. Tumour stages cT1-T2 were associated with a lower probability of being discussed at a MDT conference as was age in the upper quartile (>79 years) (Table 9 and Figure 4). Figure 4 . #!$'$. .

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(46) RESULTS. Table 9: Factors associated with preoperative MDT conference (n=4883) . n. . MDT/Total. Hospital volume Very low Low. Univariate analysis OR. 95% CI. p-value. 784/1175 (67%). Multivariate analysis OR. 95% CI. 0.15. p-value . 0.12-0.19. <0.001. 0.15. 0.12-0.20. <0.001. 1036/1303 (80%) 0.29 0.22-0.38. <0.001. 0.27 0.21-0.36. <0.001. Intermediate. 1107/1190 (93%). 1.00. REF. 1.00. REF. . High. 1124/1200 (94%). 1.11. 0.80-1.53. 0.529. 0.99. 0.71-1.38. 0.944. 0.30 0.08-1.09. 0.066. 0.55. 0.14-2.18. 0.395. . . . . Unknown ASA grade. 12/15 (80%) . . . 1. 826/976 (85%). 2. 2113/2443 (86%). 1.00. REF. 3. 801/954 (84%). 0.82. 0.66-1.01. 4 Unknown Age (years) <72. 0.86 0.70-1.06. 0.157. 0.84 0.66-1.06 1.00. 0.058. REF. 0.82 0.65-1.04. 0.098. 46/63 (73%). 0.42 0.24-0.75. 0.003. 0.52 0.28-0.99. 0.045. 277/447 (62%). 0.25 0.20-0.32. <0.001. 0.33 0.26-0.43. <0.001. . . 2284/2646 (86%) 1.00. REF. . 1.00. REF 0.81-1.25. 72–79. 1031/1223 (84%). 0.85 0.70-1.03. 0.096. 1.01. >79. 748/1014 (74%). 0.45 0.37-0.53. <0.001. 0.60 0.48-0.74. Gender. 0.135. . . 0.928 <0.001. . . . . . Woman. 2398/2874 (83%) 0.96. 0.83-1.12. 0.606. 0.98. 0.83-1.17. 0.825. Man. 1665/2009 (83%) 1.00. REF. . 1.00. REF. . Tumour stage. . . I–II. 1091/1300 (84%) 0.59 0.48-0.73. III. 1845/2055 (90%) 1.00. <0.001. REF. . 0.54 0.43-0.67. <0.001. 1.00. REF. . IV. 707/780 (91%). 1.10. 0.83-1.46. 0.495. 1.12. 0.83-1.51. 0.461. Unknown. 420/748 (56%). 0.15. 0.12-0.18. <0.001. 0.16. 0.13-0.20. <0.001. Patients with metastatic disease or with relevant data missing were excluded (Figure 1). The multivariate analysis is adjusted for hospital volume, ASA grade, age, gender and tumour stage but not for interactions. MDT = multidisciplinary team. OR = odds ratio. CI 95% = confidence interval of 95%. ASA = American Society of Anesthesiologists. Lowest tolerance statistic 0.650. 29.

(47) RESULTS. Patients with pT3c, pT3d and pT4 tumours as well as patients with pN+ tumours who were discussed at a preoperative MDT conference had a higher likelihood of receiving preoperative radiotherapy (Table 10, Table 11 and Figure 5). For both pT3c-pT4 patients and pN+ patients, higher age and greater co-morbidity (ASA 3) were associated with lower use of radiotherapy. For patients with cT1T2 cN0 tumours who underwent anterior resection MDT conference did not show any significant association with radiotherapy (OR 1.14 CI95% 0.68-1.92). Figure 5.. . . "#$#. . . . . .

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(55). !. MDT conference discussion in relation to preoperative radiotherapy for T3c-T4 tumours (left) and pN+ tumours (right).. 30.

(56) RESULTS. Table 10: System-related and patient-related factors in relation to preoperative radiotherapy (pT3c, pT3d and pT4 tumours, n=1043) . n. . RT/Total. Univariate analysis OR. 95% CI. Multivariate analysis. p-value. OR. 95% CI. p-value. <0.001. 5.06. 3.08-8.34. <0.001. 1.00. REF. . . . . MDT. . Yes. 729/939 (78%) 4.38 2.89-6.64. No. 46/104 (44%). 1.00. REF. Hospital volume. . . . . Very low. 153/224 (68%). 0.77. 0.52-1.15. 0.202. 1.21. 0.76-1.94. 0.428. Low. 212/271 (78%). 1.29. 0.86-1.93. 0.226. 2.03. 1.28-3.22. 0.003. Intermediate. 179/243 (74%). 1.00. REF. 1.00. REF. . High. 231/395 (76%). 1.12. 0.76-1.64. 0.578. 1.02. 0.66-1.56. 0.939. 0/0. . . . . . . 152/188 (81%). 1.17. 0.77-1.76. 0.467. 0.90. 0.57-1.41. 0.631. Missing ASA grade 1. . 2. 460/587 (78%) 1.00. 1.00. REF. . 3. 143/239 (60%). 0.41 0.30-0.80. <0.001. 0.55. 0.38-0.79. 0.001. 4. 7/7 (50%). 0.28 0.10-0.80. 0.276. 0.28 0.08-0.90. 0.033. 13/15 (87%). 1.80 0.40-8.06. 0.445. 5.10 0.98-26.42. 0.052. Missing Age (years). REF. . . . <72. 513/612 (84%). 1.00. REF. 72-79. 178/258 (69%) 0.43 0.31-0.60. >79. 84/173 (49%). 0.18. 0.13-0.26. 330/451 (73%). 1.00. REF. APE. 311/370 (84%). 1.93. 1.37-2.74. HA. 134/222 (60%) 0.56 0.40-0.79. . . . 1.00. REF. . <0.001. 0.47. 0.32-0.69. <0.001. <0.001. 0.20. 0.13-0.31. <0.001. 1.00. REF. . Operation type AR. . <0.001. 2.57. 1.75-3.79. <0.001. 0.001. 0.92. 0.62-1.36. 0.670. Patients with emergency resection or with relevant data missing were excluded (Figure 2). The multivariate analysis is adjusted for MDT, hospital volume, ASA grade, age and operation type but not for interactions. RT = preoperative radiotherapy (any kind). MDT = multidisciplinary team. OR = odds ratio. CI 95% = confidence interval of 95%. ASA = American Society of Anesthesiologists. AR = anterior resection. APE = abdominoperineal excision. HA = Hartmann’s procedure. Lowest tolerance statistic 0.608.. 31.

(57) RESULTS. Table 11: System-related and patient-related factors in relation to preoperative radiotherapy (N1 and pN2 tumours, n=1991) . n. . RT/Total. MDT Yes No. Univariate analysis OR. 95% CI. 1283/1706 (75%) 3.83 2.96-4.96 1.00. REF. Hospital volume. . . . Very low. 320/506 (63%). Low. 397/552 (72%). Intermediate High ASA grade. <0.001. p-value . 3.55 2.60-4.85. <0.001. REF. . . . . . 0.62 0.47-0.81. 0.001. 0.95. 0.69-1.31. 0.732. 0.92. 0.70-1.21. 0.558. 1.18. 0.87-1.61. 0.286. 345/469 (74%). 1.00. REF. 1.00. REF. . 347/464 (75%). 1.07 0.80-1.43. 0.669. 0.90. 0.66-1.24. 0.530. . . . 0.228. 0/0. . . 335/440 (76%). 2. 809/1104 (73%). 3. 217/381 (57%). 4 Age (years). 95% CI. 1.00. 1. Missing. OR . 126/285 (44%). Missing. p-value. . Multivariate analysis. 1.16. 0.90-1.50. 1.00. REF. . 0.248. 0.84. 0.63-1.12. 1.00. REF. 0.48 0.38-0.62. <0.001. 0.60 0.45-0.79. <0.001. 10/20 (50). 0.37 0.15-0.89. 0.026. 0.40. 0.14-1.11. 0.079. 38/46 (83%). 1.73 0.80-3.76. 0.164. 3.10. 1.31-7.34. 0.010. . . . . 1.00. REF. . . . . <72. 953/1192 (80%). 1.00. REF. 72-79. 332/479 (69%). 0.57 0.45-0.72. <0.001. 0.57 0.43-0.74. <0.001. >79. 124/320 (39%). 0.16. <0.001. 0.16. <0.001. Operation type. 0.12-0.21. . 0.12-0.22. REF. . . AR. 644/956 (67%). 1.00. 1.00. REF. . APE. 595/717 (83%). 2.36 1.86-3.00. <0.001. 3.13. 2.40-4.08. <0.001. HA. 170/318 (53%). 0.56 0.43-0.72. <0.001. 1.09. 0.80-1.48. 0.608. Patients with emergency resection or with relevant data missing were excluded (Figure 2). The multivariate analysis is adjusted for MDT, hospital volume, ASA grade, age and operation type but not for interactions. RT = preoperative radiotherapy (any kind). MDT = multidisciplinary team. OR = odds ratio. CI 95% = confidence interval of 95%. ASA = American Society of Anesthesiologists. AR = anterior resection. APE = abdominoperineal excision. HA = Hartmann’s procedure. Lowest tolerance statistic 0.583.. 32.

(58) RESULTS. Study IV Of the 463 patients analysed, 104 (22%) had a locoregional recurrence. Only emergency surgery and stage among the factors analysed had a significant effect on the risk for locoregional recurrence (Table 12 and Figure 6). When T4 tumours were excluded, the relationship between perforation/abscess and locoregional recurrence became stronger 2.65 (1.23-4.06) p 0.008. The effect of the other independent variables did not change significantly. When the variable “perforation discovered at surgery” was used instead of the variable “indication for emergency surgery”, perforation had a much weaker impact on the risk for local recurrence. Interestingly, this observation was evident despite the fact that the number of perforations found during surgery was higher than the number of perforations leading to emergency intervention (Table 12). Figure 6.. Kaplan-Meier curve for cumulative incidence of locoregional recurrence after potentially curative emergency resection according to the cause for emergency surgery.. 33.

(59) 34 38. Unknown. 139 53. >300ml. Unknown. 224 135. Negative. 34. Positvie. 84. 302. III. IV 66. 38. 19. 1. 15. 44. 45. 23. I-II. 167. 50. 0-300ml. 27. 136. 3-4. Unknown. 19. 58. 11. 29. 64. 57. 47. 2. 23. 79. 8. 2. 17. 77. 173. 1-2. 89. 18.00-06.59. 181 232. >1 days. 07.00-17.59. 178. 7. 0-1 days. 52. Peroperative. 45. Other. Preoperative. 11. Bleeding 300. 34. Perforation/Abscess. None. 269. Obstruction. 2.70. 1.00. 3.19. 1.00. 0.17. 1.01. 1.21. 1.00. 1.23. 0.83. 1.00. 1.16. 1.32. 1.00. 1.00. 1.17. 1.13. 1.63. 1.00. 0.67. 0.75. 1.75. 1.00. 1.80-4.02. REF. 1.37-3.70. REF. 0.02-1.24. 0.56-1.80. 0.80-1.83. REF. 0.74-2.07. 0.53-1.32. REF. 0.61-2.21. 0.85-2.05. REF. REF. 0.80-1.73. 0.28-4.61. 1.02-2.59. REF. 0.32-1.39. 0.18-3.04. 1.04-2.96. REF. 95% CI. <0.001. . 0.001. . 0.081. 0.986. 0.373. . 0.425. 0.439. . 0.642. 0.216. . . 0.419. 0.861. 0.039. . 0.280. 0.684. 0.037. . p-value. Univariate analysis HR. Cox proportional hazard model. HR = hazard ratio. CI = confidence interval.. N-stage. T-stage. Blood loss. ASA score. Start of operation. Time to operation. Perforation. Cause of emergency. No. . Yes. Recurrence. . Table 12: Risk factors for local recurrence.. 2.54. 1.00. 1.97. 1.00. 0.18. 0.78. 1.21. 1.00. 1.16. 0.84. 1.00. 1.56. 1.28. 1.00. 1.00. 0.96. . . . 0.79. 1.08. 1.96. 1.00. 1.68-3.82. REF. 1.17-3.32. REF. 0.03-1.35. 0.35-1.76. 0.79-1.85. REF. 0.62-2.19. 0.52-1.33. REF. 0.57-4.28. 0.80-2.07. REF. REF. 0.63-1.47. . . . 0.38-1.66. 0.26-4.53. 1.12-3.43. REF. 95% CI. <0.001. . 0.011. . 0.096. 0.565. 0.384. . 0.643. 0.452. . 0.392. 0.298. . . 0.845. . . . 0.532. 0.921. 0.018. . p-value. Multivariate analysis HR. 2.51. 1.00. 2.04. 1.00. 0.20. 0.76. 1.18. 1.00. 1.17. 0.83. 1.00. 1.54. 1.28. 1.00. 1.00. 1.03. 1.01. 1.63. 1.00. . . . . 1.67-3.77. REF. 1.21-3.44. REF. 0.03-1.43. 0.33-1.74. 0.77-1.80. REF. 0.62-2.21. 0.52-1.32. REF. 0.55-4.35. 0.79-2.07. REF. REF. 0.68-1.55. 0.24-4.19. 1.00-2.66. REF. . . . . 95% CI. <0.001. . 0.008. . 0.108. 0.518. 0.451. . 0.620. 0.430. . 0.415. 0.310. . . 0.908. 0.993. 0.049. . . . . . p-value. Multivariate analysis HR. RESULTS.

(60) RESULTS. If surgery was performed during the day, the mean blood loss was 444ml (median 300ml) whereas the corresponding volume where surgery was performed at night was 418ml (median 300ml). There was no difference in the proportion of patients bleeding more than 300ml (Table 13 and Figure 7) Table 13: Start of operation and blood loss 0-300ml. >300ml. 07.00–17.59. 147 (52%). 137 (48%). 18.00–06.59. 62 (59%). 43 (41%). Cross-tabulation showing the number of patients with blood loss more or less than 300ml operated during the day versus at night. P = 0.201 (Pearson’s chi square test).. Figure 7.. Scatter plot to show the relationship between blood loss and start time for emergency colon cancer resection.. Of all the 463 patients included, 225 (49%) had their operation within the same day as the admission. Furthermore, of the 414 patients where the start time of the operation was known, 296 (72%) operations began between 07.00 and 17.59. The distribution of causes for emergency surgery was 346 patients with ileus (75%), 51 patients with perforation or abscess (11%), 13 patients with bleeding (3%), and 53 patients with other cause (11%).. 35.

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