Effect of Different Durations of Adjuvant Capecitabine Monotherapy on the Outcome of High-Risk Stage II and Stage III Colorectal Cancer: A Retrospective Study Based on a CRC Database.

(1) Background: The duration of adjuvant chemotherapy recommended by the NCCN guidelines is 6 months. However, patients are not compliant with intravenous chemotherapy for many reasons; therefore, one approach is to obtain a survival benefit by prolonging the duration of capecitabine monotherapy. (2) Methods: A total of 355 qualified colorectal cancer (CRC) patients from January 2010 to December 2020 at West China Hospital of Sichuan University were selected to receive capecitabine monotherapy for 6−9 months and >12 months. The main endpoints were overall survival (OS) and disease-free survival (DFS). (3) Results: Among stage III patients, in the >12 months (12M) and 6−9 months (6M) groups, the 5-year DFS rates were 80.7%% and 66.8%, respectively, and the 5-year OS rates were 94.7%% and 88.8%, respectively. Among high-risk stage II patients, in the >12 months (12M) and 6−9 months (6M) groups, the 5-year DFS rates were 81.5% and 78.6%, respectively, and the 5-year OS rates were 93.1% and 84.2%, respectively. (4) Conclusions: Twelve months of chemotherapy demonstrated superior OS and DFS to that of six months in the stage III group but showed no difference in the high-risk stage II group. The better OS and DFS observed in the 12-month treatment period could be of value in selected cases.