Evaluation of the Leftover Capecitabine Tablets in Adjuvant CAPOX Chemotherapy for Gastric Cancer

Since it is important that patients take their oral anticancer therapy as prescribed, pharmacists need to assess adherence. In addition, oral anticancer drugs are expensive, and reuse of leftover drugs at outpatient pharmacy clinics is useful in reducing drug costs. The present study aimed to clarify when and why patients have leftover capecitabine tablets, and the cost of leftover capecitabine tablets reused at an outpatient pharmacy clinic, focusing on adjuvant capecitabine plus oxaliplatin (CAPOX) chemotherapy for gastric cancer. We retrospectively studied patients who received adjuvant CAPOX chemotherapy for gastric cancer between November 1, 2015, and April 30, 2021, at the Cancer Institute Hospital of the Japanese Foundation for Cancer Research. The cost of leftover capecitabine reused by pharmacists was calculated based on the National Health Insurance drug price standard for the study period. This study included 64 patients who received adjuvant CAPOX chemotherapy. Thirty-seven patients had 152 leftover capecitabine tablets. The most common reasons for leftover capecitabine tablets were nausea and vomiting (21.7%), missed doses (18.4%), and diarrhea (13.2%). The leftover capecitabine tablets for 25 patients were reused at the outpatient pharmacy clinic at a cost of JPY 604142.8 (JPY 24165.7 per patient). The study results suggest that evaluating capecitabine adherence and the reasons for leftover capecitabine tablets at outpatient pharmacy clinics as well as reusing leftover medication can contribute to reducing drug costs.