Adjuvant chemotherapy improves survival in patients with American Joint Committee on Cancer stage II colon cancer

It is unclear whether the administration of adjuvant chemotherapy improves survival in patients with American Joint Committee on Cancer (AJCC) stage II colon cancer.

The authors used the State of California Cancer Surveillance Program (CSP) to assess patients ages 18 to 80 years with AJCC stage II colon cancer (ie, T3 or T4 and N0) who underwent surgical resection during 1991 and 2006. Patients who had rectal and rectosigmoid cancers were excluded. The cohort was stratified according to the receipt of adjuvant chemotherapy, and clinical and pathologic characteristics and outcomes were assessed.

From the CSP data, 3716 patients were identified who underwent curative-intent surgical resection for stage II colon cancer. When the 2 treatment groups (surgery plus adjuvant chemotherapy [n = 916] and surgery alone [n = 2800]) were compared, patients who received adjuvant chemotherapy were more likely to be younger and to have left-sided lesions with ≥ 12 lymph nodes examined. There was no difference in sex or tumor differentiation between the 2 groups. According to a Kaplan-Meier analysis, patients who received adjuvant chemotherapy had improved overall survival compared with patients who underwent surgery alone (median survival, 12 years vs 9.2 years, respectively; P < .001). In multivariate analysis, adjuvant chemotherapy was identified as an independent predictor of improved survival (hazard ratio, 0.88; 95% confidence interval, 0.78-0.99; P = .031).

To the authors' knowledge, this is the first population-based analysis to identify a survival advantage for adjuvant chemotherapy in patients with AJCC stage II colon cancer. On the basis of the current findings, the authors concluded that the administration of adjuvant chemotherapy improves survival in select patients with stage II disease.