Lymph node involvement in colon cancer patients decreases with age; a population based analysis

Background: The variation in nodal involvement between age groups has not been thoroughly studied in colon cancer, but it may affect strategies for extent of resection in elderly patients. The objective of Our study was to compare nodal involvement in colon cancer patients, with a focus on surgical staging practices in the elderly. Methods: We extracted data from the Surveillance, Epidemiology and End Results registry on 208,077 patients diagnosed with stage colon adenocarcinoma between 2000 and 2010. Patients undergoing colon resection, patients with adequate staging with >= 12 lymph nodes examined (LNE, n = 114,351) and with node-positive cancers were compared in age groups using chi-squared test. Relative risk (RR) of node-positive cancer was compared in a multivariable log-linear model, and relative survival in a flexible parametric model. Results: While the rates of colon resection were similar in all age groups, older patients were significantly less likely to have >= 12 LNE (P < 0.0001). When adequately staged, older patients had a significantly lower proportion of node-positive cancers (P < 0.0001). Survival was better in patients with >= 12 LNE, with no significant difference in the benefit between the age groups (P = 0.25). Conclusions: When adequately staged, older patients are less likely to have node positive colon cancer, which may help them avoid adjuvant chemotherapy. Since the survival benefit of adequate nodal staging is similar in every age group, the guidelines for extent of resection and pathological examination should be diligently adhered to in all patients undergoing curative surgery, regardless of age. (C) 2014 Elsevier Ltd. All rights reserved.