Risks and Outcomes of Early Dose Reduction in Adjuvant CAPOX Therapy for Colorectal Cancer

Abstract

Background/aim: Adjuvant capecitabine and oxaliplatin (CAPOX) therapy is standard strategy for colorectal cancer with risk of recurrence. Early dose reduction (EDR) of CAPOX therapy is commonly used in real-world practice. However, there is limited evidence regarding the effectiveness of CAPOX for patients who had EDR. Therefore, this study aimed to clarify the risks of EDR and its effect on long-term outcomes and body composition factors.

Patients and methods: Patients who received CAPOX therapy after radical surgery for colorectal cancer between June 2013 and December 2021 were included. EDR was defined as dose reduction within four courses of CAPOX therapy. Body composition factors were measured for 1 year following surgery to determine the EDR effects.

Results: Eighty-four patients were included; 35 (42%) of them had EDR. The multivariate analysis revealed that underweight [odds ratio (OR)=4.95, 95% confidence interval (CI)=1.13-21.7, p=0.03] was a risk factor for EDR. Relapse-free survival (RFS) was significantly better in the non-EDR group (p=0.01). The 5-year RFS rates for the non-EDR and EDR groups were 88.7% and 65.4%, respectively. The multivariate analysis revealed that age >65 years [hazard ratio (HR)=3.97; 95% CI=1.16-13.62, p=0.03] and EDR (HR=7.62; 95% CI=1.71-33.91, p=0.005) were associated with poorer RFS. The 1-year body composition analysis revealed decreases in all factors in the EDR group.

Conclusion: Preoperative underweight status was associated with EDR, which resulted in decreased RFS and body composition factors when compared with the non-EDR group. Therefore, avoiding EDR and early nutritional intervention after EDR may improve outcomes.

Keywords: CAPOX; Colorectal cancer; adjuvant therapy; body composition factor; early dose reduction; underweight.