Background: Contemporary treatment of node-positive (N+) colon cancer consists of adjuvant chemotherapy; however, randomized data supporting this practice were derived from lesions T2 or greater. Minimal data exist regarding the use and need for adjuvant chemotherapy in T1N+ disease.
Objective: The aim of this study was to determine treatment trends and the effects of adjuvant chemotherapy on T1N+ colon cancers by using the National Cancer Database.
Design: This was a retrospective study. Baseline demographics, tumor, and cancer treatment characteristics were compared. Groups were matched on the propensity to receive chemotherapy. Adjusted long-term survival stratified by chemotherapy use was compared by using the Kaplan-Meier method with the log-rank test. Predictors of not receiving chemotherapy were identified by using a multivariable logistic regression model.
Settings: Data were collected from the National Cancer Database, which collects cancer data from over 1500 cancer centers.
Patients: We identified patients from 1998 to 2006 with T1N+ disease, excluding those with metastatic disease or previous cancer. Patients were stratified based on whether or not they received chemotherapy.
Main outcome measures: The primary outcome measure of this study was long-term survival.
Results: Three thousand one hundred thirty-seven patients had T1N+ disease; 70.6% (n = 2216) received chemotherapy, and utilization significantly increased from 1998 to 2011 (p < 0.001). Unadjusted analysis revealed that patients treated with chemotherapy were statistically younger and healthier, and had shorter postoperative lengths of stay (all p < 0.001). Unadjusted 5-year survival was higher in patients receiving chemotherapy (87.9% vs 63.0% in patients with no chemotherapy; p < 0.001) and this persisted after propensity matching with (83.4% and 63.0% in patients with or without chemotherapy; p < 0.001). Only age (OR, 0.29; p < 0.001) predicted not receiving chemotherapy.
Limitations: Limitations include potential selection bias as well as the inability to compare disease-free survival/recurrence.
Conclusions: Adjuvant chemotherapy appears to significantly improve long-term survival in patients receiving chemotherapy in T1N+ disease. Thus, the use of chemotherapy in T1N+ disease is justified and provides a highly significant survival benefit.