Background: Improved survival is associated with an increased number of lymph nodes (LNs) examined. The aim of this study was to assess whether the examination of >or=12 LNs is associated with more accurate colon cancer staging.
Methods: We queried the Department of Defense Automated Central Tumor Registry database for stage I-III colon cancer patients. Logistic regression analysis was performed to determine whether the examination of >or=12 LNs is associated with increased rates of LN-positive colon cancer. Kaplan-Meier and Cox proportional hazard analysis was performed to evaluate the effect of number of LNs examined on survival.
Results: The rate of LN-positive colon cancer is significantly higher with increasing number of LNs examined (1-3 LNs examined: 31% vs. >12 LNs examined: 41%, P<.001). Logistic regression analysis adjusting for patients, tumor, and hospital characteristics showed that examination of >or=12 LNs is associated with a >30% increase in detecting a LN-positive colon cancer (odds ratio, 1.350; 95% confidence interval, 1.175-1.511). The evaluation of >or=12 LNs is associated with improved survival in LN-negative colon cancer patients (P<.001).
Conclusions: Our study demonstrates that the proportion of LN-positive colon cancer is far higher when >or=12 LNs are examined. Examination of >or=12 LNs may improve staging accuracy and outcome with optimal use of systemic chemotherapy.