Background: Retrieval of >/= 12 lymph nodes has been set as a marker of quality for surgical resection for colon cancer. The aim of our study was to determine if increasing the number of lymph nodes recovered in stage III colon cancer results in improved survival and if it does represent a reasonable quality metric.
Study design: Data from patients with stage III colon cancer from 1996 to 2001 were analyzed. Outcomes after operation (cancer-specific survival, disease-free survival, and overall survival) with or without adjuvant therapy were evaluated in 3 categories: the entire cohort, patients with N1, and patients with N2 disease. These categories were then classified into subgroups by the number of nodes (</= 12 versus >12) retrieved per specimen and whether they had 5-FU-based chemotherapy or not.
Results: Three hundred twenty-nine patients, with a median followup of 5 years with stage III colon cancer, were identified. Five-year cancer-specific and disease-free survival was 67.2% and 59.7%, respectively. A positive correlation between number of positive lymph nodes and overall survival was found (p < 0.05). No significant association was observed between the total number (> 12 versus </= 12) of lymph nodes removed either in the entire cohort or in patients with N1 (249 patients) and N2 (80 patients) disease.
Conclusion: Accurate staging requires an appropriate operation and a concerted pathologic effort to identify lymph nodes in the colon specimen. The total number of lymph nodes analyzed for stage III colon cancer is not a prognostic indicator of cancer-specific and disease-free survival.