The impact of surgeon and pathologist on lymph node retrieval in colorectal cancer and its impact on survival for patients with Dukes’ stage B disease

OBJECTIVE: An adequate lymph node harvest is necessary for accurate Dukes' stage discrimination in colorectal cancer. The aim of this study is to identify the effect of variables, including the individual surgeon and pathologist, on lymph node harvest in a single institution. METHOD: Three hundred and eighty one consecutive patients had resection for colorectal cancer, in a single unit. Factors influencing lymph node retrieval, including individual surgeon and reporting pathologist, were subjected to uni- and multivariate analysis. Actuarial survival of all patients with Dukes' stage B and C disease was then calculated and survival compared between Dukes' stage B and C at differing levels of lymph node harvest. RESULTS: The unit median lymph node harvest was 13 nodes/patient (95% CI 13.1-14.5). There was no difference in lymph node harvest between specialist colorectal surgeons and the pooled results of four nonspecialist consultant surgeons. However, there was a significant difference between reporting pathologists (P < 0.001). On univariate analysis, operation type, operative urgency, Dukes' stage, T-stage, reporting pathologist and use of neoadjuvant therapy in rectal cancer, were found to significantly affect lymph node retrieval. On multivariate analysis, operation type, T-stage, reporting pathologist and neoadjuvant therapy in rectal cancer remained significant variables. Patients with one or more lymph node metastasis had greater nodal harvests than those without (median 15 vs 12 P = 0.02). Survival of patients with Dukes' stage B disease was found to improve as lymph node harvest increased. CONCLUSION: Overall lymph node harvest, in this unit, varied according to the reporting pathologist but not operating surgeon. As lymph node harvest increased to 15 per patient, the probability of identifying a metastatic node increased.