Benefit of oxaliplatin-based chemotherapy or capecitabine monotherapy in older patients with stage III and high-risk stage II colon cancer: Data from the National Colorectal Cancer Cohort study in China

Background: Adjuvant chemotherapy is the standard management approach for patients with stage II/III colon cancer; However, the effectiveness in older patients is still unclear. This study aimed to explore the efficacy of adjuvant chemotherapy and whether oxaliplatin-based chemotherapy has better oncological outcomes than capecitabine monotherapy in older patients with stage III and high-risk stage II colon cancer. Methods: We analyzed and compared oxaliplatin-based adjuvant chemotherapy with capecitabine monotherapy and no chemotherapy in 468 patients aged ≥70 years with stage III and high-risk stage II colon cancer, and a propensity score-matched analysis was conducted. The endpoints were overall survival (OS), cancer-specific survival (CSS), local recurrence-free survival (LRFS), and distant metastasis-free survival (DMFS). Results: Firstly, this study compared adjuvant chemotherapy with no adjuvant chemotherapy, statistically significant differences were observed in OS and CSS at the treatment arm and age groups (5-year OS rate: 84.6% vs . 65.9%, P <0.001; 5-year CSS rate: 87.9% vs . 77.5%, P = 0.012), but no difference was observed in LRFS or DMFS. The subgroup analysis suggested that no statistically significant benefits were observed between oxaliplatin-based adjuvant chemotherapy and capecitabine monotherapy, and no significant differences in chemotherapy duration were detected with ≥6 months of therapy compared with 3–6 months (exluding 6 months) of therapy. Conclusion: Older patients with stage III or high-risk stage II colon cancer can benefit from adjuvant chemotherapy, and capecitabine monotherapy has non-inferior oncological outcomes compared with oxaliplatin-based regimens. Clinical trial number: ClinicalTrials.gov, NCT04074538.