gms | German Medical Science

122. Kongress der Deutschen Gesellschaft für Chirurgie

Deutsche Gesellschaft für Chirurgie

05. bis 08.04.2005, München

The Influence of the Surgeon’s and the Hospital’s Caseload on Survival and Local Recurrence after Colorectal Cancer Surgery

Meeting Abstract

  • corresponding author P. Renzulli - Swiss Group for Clinical Cancer Research (SAKK)
  • A. Lowy - Swiss Group for Clinical Cancer Research (SAKK)
  • R. Maibach - Swiss Group for Clinical Cancer Research (SAKK)
  • R. A. Egeli - Swiss Group for Clinical Cancer Research (SAKK)
  • U. Metzger - Swiss Group for Clinical Cancer Research (SAKK)
  • U. T. Laffer - Swiss Group for Clinical Cancer Research (SAKK)

Deutsche Gesellschaft für Chirurgie. 122. Kongress der Deutschen Gesellschaft für Chirurgie. München, 05.-08.04.2005. Düsseldorf, Köln: German Medical Science; 2005. Doc05dgch2377

The electronic version of this article is the complete one and can be found online at:

Published: June 15, 2005

© 2005 Renzulli et al.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License ( You are free: to Share – to copy, distribute and transmit the work, provided the original author and source are credited.




Past studies have identified the individual surgeon as well as surgeon- and institution- related characteristics as prognostic factors in colorectal cancer surgery. The present work assesses the influence of the surgeon's caseload, the surgeon's grade and the hospital's caseload on long-term results of colorectal cancer surgery.


The data on 2706 patients from two randomized colorectal cancer trials (SAKK 40/81, 40/87) and one concurrent registration study (SAKK 40/88) were reviewed. The randomized trials investigated adjuvant intraportal and systemic chemotherapy in non-metastatic colorectal cancer patients. All three studies were multi-center trials with a total of 26 participating hospitals (6 university, 20 regional or district hospitals). A first analysis included 1809 eligible non-metastatic patients from all three studies. A subsequent subgroup analysis included 915 eligible patients from both randomized trials. Overall survival (OS), disease-free survival (DFS) and local recurrence (LR) were analyzed in multivariate models. The main potential covariates were: surgeon's annual caseload (>5 operations/year vs. ≤5 operations/year), surgeon's grade (senior surgeon vs. surgeon vs. trainee), hospital's annual caseload (>26 operations/year vs. ≤26 operations/year), tumor site, T-stage and nodal status. Stratifications for the surgeon's and the hospital's caseloads (cut-off values of 5 and 26 operations/year, respectively) were based on the median in order to maximize statistical power. Calculation of the surgeon's and hospital's caseload was based on the dataset of 2706 patients.


Primary analysis of all three studies combined found a high surgeon's caseload to be positively associated with OS (p=0.025) and marginally with DFS (p=0.058). Separate analysis for each trial, however, showed that a high surgeon's caseload was beneficial in both randomized trials but not in the registration study (SAKK 40/88; OS p=0.75, DFS p=0.76), due to higher co-morbidity and age. A subgroup analysis of 915 patients from both randomized trials was therefore performed. There were 376 rectal and 539 colonic primaries operated on by 94 surgeons and 38 senior surgeons. The analysis found that both high surgeon's and high hospital's annual caseloads were independent beneficial prognostic factors for OS (p=0.0001, p=0.009), DFS (p=0.0008, p=0.02) and marginally for LR (p=0.054, p=0.05), whereas the surgeon's grade showed no association with outcome. Further analysis showed that neither age, sex, year of operation, adjuvant chemotherapy (intraportal vs. systemic vs. surgery alone), hospital's status (university vs. non-university hospital), training status of the surgeon (board-certified surgeon vs. trainee), nor the inclusion in one of the two randomized trials (SAKK 40/81 vs. 40/87) were significant predictors of outcome. Furthermore a beneficial interaction between the surgeon's and the hospital's caseloads was found. Patients operated on by low-caseload surgeons in high-caseload hospitals had a significantly better outcome than patients operated on by low-caseload surgeons in low-caseload hospitals (OS p=0.0008, DFS p=0.001, LR p=0.04). Finally, the beneficial impact of higher caseload applied to rectal as well as colonic cancer. [Tab. 1]


Higher surgeon's and hospital's annual caseloads were strong independent prognostic factors extending overall and disease-free survival and reducing the rate of local recurrence in two randomized colorectal cancer trials.