Background: Up to 6-months oxaliplatin-containing regimen is now widely accepted as a standard adjuvant chemotherapy for stage III colorectal cancer (CRC). However, oral fluoropyrimidine monotherapy is used for some part of patients, especially in Asian countries including Japan, and its optimal duration is yet to be fully investigated.
Methods: A total of 1306 patients with curatively-resected stage III CRC were randomly assigned to receive capecitabine (2500 mg/m2/day) for 14 out of 21 days for 6 (n = 654) or 12 (n = 650) months. The primary endpoint was disease-free survival (DFS), and the secondary endpoints were relapse-free survival (RFS), overall survival (OS), and adverse events.
Results: The 3- and 5-year DFS were 70.0% and 65.3% in the 6M group and 75.3% and 68.7% in the 12M group, respectively (p = 0.0549, HR = 0.858, 90% CI: 0.732-1.004). The 5-year RFS was 69.3% and 74.1% in the 6M and 12M groups, respectively (p = 0.0143, HR = 0.796, 90% CI: 0.670-0.945). The 5-year OS was 83.2% and 87.6%, respectively (p = 0.0124, HR = 0.727, 90% CI: 0.575-0.919). The incidence of overall grade 3-4 adverse events was almost comparable in both groups.
Conclusions: Although 12-month adjuvant capecitabine did not demonstrate superior DFS to that of 6-month, the observed better RFS and OS in the 12-month treatment period could be of value in selected cases.