Which Lymph Nodes Contain Metastases in Colon Cancer Patients? A Retrospective Histopathological Evaluation of 156 Patients

BACKGROUND: We hypothesized that a reliable N0 status can be established by sampling and evaluating the largest lymph nodes in the resected large-bowel specimen of patients with colon cancer. PATIENTS AND METHODS: This was a retrospective analysis of all surgical colon cancer patients treated between 2008 and 2010, excluding those who had received neoadjuvant treatment. We analyzed the relationship between lymph node size and the presence of metastasis. Furthermore, we examined other prognostic factors for a histopathological N+ status. RESULTS: Our patient group consisted of 156 patients with a median age of 73 years (range = 29-91 years). A total of 2044 lymph nodes (a median of 12 per patient, range = 2-47 nodes) were harvested, 1803 (88.2%) without and 241 (11.8%) with tumor spread. Using a unique ranking model, we found that in 58 out of the 59 N+ patients (98.3%, 95% confidence interval = 90.9% to 99.9%), the largest tumor-positive node was among the 5 largest lymph nodes in the specimen. The examination of ≥10 lymph nodes had no effect on the chance of finding a positive lymph node compared with examination of <10 nodes (P = .46). CONCLUSION: In our study, the N-stage was determined by the 5 largest nodes in almost all specimens. The chance of finding a small tumor-positive node when the larger ones were clean was very small.