Evaluation of the efficacy of adjuvant chemotherapy in patients with high-risk stage II colon cancer.

PURPOSE This study aimed at comparing the disease-free survival (DFS) in high-risk TNM stage II colon cancer patients who had been subjected to adjuvant chemotherapy and TNM low-risk stage II patients who did not receive chemotherapy. METHODS We retrospectively reviewed the medical records of stage II colon cancer patients between January 2006 and December 2011. High-risk patients were defined those with any colonic obstruction/perforation, mucinous histology, inadequate lymph node sampling, T4 disease, lymphatic/ vascular or perineural invasion, preoperatively elevated carcinoembryonic antigen (CEA) and high-grade tumor. All patients with high-risk features received adjuvant chemotherapy. RESULTS There were 42 patients in the high-risk treatment group and 21 patients in the non-treatment (observation) group. There were no significant differences in terms of gender, tumor size, tumor localization, or the number of excised lymph nodes between the groups. The median follow- up time was 33.9 months in the treatment group and 29.3 months in the non-treatment group. Recurrence developed in 4 patients (6.3%), 3 of which were in the treatment group. DFS in both groups was statistically similar. CONCLUSION Adjuvant chemotherapy in the high-risk patients resulted in similar DFS as that in the low-risk patients. Although the role of adjuvant chemotherapy for stage II colon cancer is unclear, it is rational to offer adjuvant chemotherapy to patients with high-risk stage II colon cancer.