The updated five-year overall survival and long-term oxaliplatin-related neurotoxicity assessment of the FACOS study

Purpose We previously reported the first evidence of oncological benefits from a Japanese phase II trial of oxaliplatin-based adjuvant chemotherapy in patients with stage III colon cancer (the FACOS study). We herein report the long-term survival and persistent oxaliplatin-related peripheral sensory neuropathy (PSN) for patients enrolled in this trial. Methods Patients were scheduled to receive the mFOLFOX6 or CAPOX regimen in the adjuvant setting. The five-year overall survival (OS) rate and persistent PSN were evaluated. Results A total of 130 patients (mFOLFOX6, n = 73; CAPOX, n = 57) were eligible. The 5-year OS rate was 91.4%. No significant difference in the OS rate was observed between regimens (mFOLFOX6, 94.4%; CAPOX, 87.4%; P = 0.25). The incidence of PSN during adjuvant treatment was 55.4% in grade 1 (G1), 30.0% in G2, and 4.6% in G3. No patients showed G3 PSN at 12 months, but G1 or G2 residual PSN after 5 years was observed in 21.8% (G1, 20%; G2, 1.8%). Conclusions Updated results from the FACOS study support the benefits of oxaliplatin-based adjuvant chemotherapy in terms of the long-term survival among Japanese patients with stage III colon cancer. However, long-term persistent PSN occurs in about 20% of survivors, counterbalancing the favorable OS.