Biweekly CAPOX versus Triweekly CAPOX in the adjuvant therapy of post-surgery CRC: a randomized controlled trial

Abstract Background: Adjuvant CAPOX (capecitabine plus oxaliplatin) provided significant disease-free survival (DFS) benefit in patients with high-risk stage II or stage III colorectal cancer (CRC). Conventional triweekly CAPOX results in 14-38% 3-4 grade hematological toxicity. Modified biweekly CAPOX was observed to be generally well-tolerated in previous studies. Methods: High-risk stage II and stage III post-surgery CRC patients were randomized in the control triweekly group (intravenous infusion of oxaliplatin 130 mg/m2 on day 1 and oral capecitabine 1000 mg/m2, twice daily from d1 to d14) and the experimental biweekly group (intravenous infusion of oxaliplatin 85 mg/m2 on day 1 and oral capecitabine 1000 mg/m2, twice daily from d1 to d10). The primary endpoint was incidence of thrombocytopenia. The secondary endpoint was 18-month DFS rate. Results: Between Jul 25, 2018, and May 14, 2021, 160 patients were 1:1 randomly enrolled and received treatment. The primary endpoint thrombocytopenia occurred 33% and 49% in biweekly and triweekly group ( P =0.02). The second endpoint 18-month DFS in 3-month group was 94.1% in biweekly CAPOX group, and 93.8% in triweekly CPOX group ( P =0.96). Neutropenia was 36% and 51% in biweekly and triweekly group, respectively ( P =0.04). The rate of uncomplete therapy patient was 7% and 15% in biweekly and triweekly group, respectively ( P =0.13). Conclusion: Biweekly CAPOX presented significant less thrombocytopenia and neutropenia than triweekly CAPOX regimen. And biweekly CAPOX did not affect the 18-month DFS rate. Clinical trial registration: First registration date: 21/06/2018. ClinicalTials.gov (NCT03564912).