Phase II clinical trial of adjuvant chemotherapy with mFOLFOX6/XELOX for stage III colon cancer in Japanese subjects

Aim/Background

In Japan, the main adjuvant chemotherapy used for colon cancer is oral 5-fluorouracil (5-FU) because the 5 year survival rate for colon cancer is good (Stage IIIA; 77.3%, Stage IIIB; 68.1%). Although the safety and efficacy of FOLFOX4 for stage III colon cancer have been reported (MOSAIC trial), there are insufficient safety data to justify the use of mFOLFOX6 and XELOX as adjuvant chemotherapy for stage III colon cancer in Japanese patients. We evaluated the efficacy, feasibility and safety of adjuvant mFOLFOX6 or XELOX in patients with Stage III colon cancer.

Methods

Inclusion criteria were as follows: 1) Stage III colon cancer; 2) age 20–75 years; 3) ECOG PS 0 or 1; and 4) curative resection. Physicians selected 12 courses of mFOLFOX6 or 8 courses of XELOX.

Results

One hundred and thirty-two patients were enrolled in this study; however, two were ineligible. The study thus included 80 men and 50 women, 88 patients with stage IIIa and 42 with stage IIIb, 44 patients with right and 86 with left colon cancer. One hundred and eighteen patients (91%) underwent D3 lymph node dissection, the median number of dissected lymph nodes being 19. Seventy-three patients received mFOLFOX6 and 57 patients XELOX. The median age was 65 years. The rate of chemotherapy completion was 69.2% (N = 90). The reasons for discontinuation were adverse events (N = 31), patient refusal to continue (N = 8), and recurrence (N = 1). The median number of cycles of mFOLFOX6 was 12 (1–12) and of XELOX was eight (1–8). The median oxaliplatin relative dose intensity was 80.3% (14.8–100%). The overall rate of grade 3–4 toxicity was 40%, of grade 3–4 neutropenia 28.5%, and of grade 3 neuropathy 4.6%. The relative dose intensity of oxaliplatin of the patients treated with XELOX tended to be higher than that of the patients treated with FOLFOX (P = 0.06). The incidences of G3–4 neutropenia (P = 0.04) and G2 infusion-related reactions (P = 0.002) in the patients treated with FOLFOX were significantly higher than in those treated with XELOX.

Conclusions

mFOLFOX6 and XELOX are safe and feasible for adjuvant chemotherapy of Japanese patients with Stage III colon cancer. In these patients, XELOX may be safer than FOLFOX. Though, this clinical study was not randomized trial with small number of patients.

Clinical trial identification

Disclosure

All authors have declared no conflicts of interest.