Objective: This multicenter, single-arm phase II study (UMIN000008429) aimed to evaluate the efficacy and safety of capecitabine plus oxaliplatin (CapOX) as postoperative adjuvant chemotherapy for patients with locally advanced rectal cancer.
Methods: Patients with resectable clinical Stage II or III rectal cancer were enrolled to receive eight cycles of CapOX therapy (130 mg/m2 oxaliplatin on day 1 and 2000 mg/m2 oral capecitabine on days 1-14, every 3 weeks) after curative surgical resection. The primary endpoint was 3-year relapse-free survival (RFS) rate, and secondary endpoints were 3-year overall survival (OS) rate, treatment compliance, and safety.
Results: A total of 40 patients (Stage II, 21; Stage III, 19) were enrolled between September 2012 and November 2015 from seven institutions. Thirty-nine patients (97%) received R0 resection, and 32 patients (84%) received postoperative CapOX therapy. The completion rate of all eight cycles of CapOX therapy was 66%. Relative dose intensities were 87% for oxaliplatin and 84% for capecitabine. At a median follow-up period of 46 months, disease recurrence was observed in nine patients, including three with local recurrence. Three-year RFS and OS rates were 75% (95% CI 57-86%) and 96% (95% CI 80-99%), respectively. Frequencies of Grade ≥ 3 hematological and non-hematologic adverse events were 19% and 38%, respectively.
Conclusion: CapOX therapy is feasible as adjuvant chemotherapy for locally advanced rectal cancer.