Oncologic outcomes after adjuvant chemotherapy using FOLFOX in MSI-H sporadic stage III colon cancer.

Abstract

BACKGROUND: Little is known of the oncological outcomes after adjuvant FOLFOX chemotherapy in patients with stage III colon cancer showing microsatellite instability high (MSI-H). In the present study we investigated the prognostic impact of MSI-H in patients with stage III colon cancer receiving FOLFOX chemotherapy.

METHODS: We analyzed the MSI status in 127 patients with stage III colon cancer who underwent curative surgical resection followed by FOLFOX chemotherapy between January 2003 and December 2010. We assessed disease-free and overall survival (OS) in patients with MSI-H colon cancer compared with those showing microsatellite instability low or microsatellite stable (MSI-L/MSS) disease.

RESULTS: Sixteen of the patients (12.6 %) were MSI-H, and 111 patients (87.4 %) were MSI-L/MSS. There was no significant difference between patients showing MSI-H and MSI-L/MSS except for age (P = 0.030), tumor location (P < 0.001), and differentiation (P = 0.031). Compared with MSI-L/MSS colon cancer, patients with MSI-H colon cancer had no significant difference in 5-year disease-free and OS (72.2 vs 68.5 %, P = 0.874; 68.1 vs 71.1 %, P = 0.437).

CONCLUSIONS: Our study indicates that FOLFOX chemotherapy can be considered to treat stage III colon cancer patients with MSI-H after surgery, although the study was not randomized and included only a limited number of patients.