Abstract
<title>Abstract</title> <p>Background Oxaliplatin-based chemotherapy as FOLFOX or CAPOX for 3 or 6 months has been the standard adjuvant treatment for stage II/III colon cancer. However, real-world data on treatment-related toxicity, adherence, and oncologic outcomes in Asian populations remains limited. This study aimed to evaluate the real-world safety, treatment adherence, and oncologic outcomes of CAPOX in Korean patients. Methods We retrospectively analyzed patients who received adjuvant CAPOX after curative resection of stage II/III colon cancer between 2011 and 2022 at four tertiary centers in Korea. Clinical, surgical, and pathological data, chemotherapy completion, dose modification, toxicities, and survival outcomes were assessed. Results Among 196 patients, 94.9% were scheduled to receive 6-month CAPOX. In the 6-month group, the completion rate was 57.0%, and grade ≥ 2 peripheral neuropathy (PN) and hand-foot syndrome (HFS) occurred in 64.5% and 54.8%, respectively. Five-year disease-free survival (DFS) and overall (OS) were favorable in stage IIA–IIIB disease (DFS 75.0-100.0% and OS 86.7–100.0%), whereas patients with stage IIIC disease demonstrated substantially worse outcomes (DFS 55.9% and OS 75.7%). In multivariable Cox regression analysis, stage IIIC disease was independently associated with worse DFS and OS, while failure to complete planned chemotherapy was associated with worse OS. Conclusion In this real-world multicenter cohort, 6-month adjuvant CAPOX was associated with significant toxicity and limited treatment adherence. Stage IIIC disease and failure to complete planned chemotherapy were independently associated with worse oncologic outcomes, highlighting the importance of completing planned adjuvant CAPOX through appropriate toxicity management and dose modification in routine clinical practice.</p>