Cost‐effectiveness of adjuvant chemotherapy for high‐risk stage II and stage III colon cancer in South Africa

BACKGROUND: Colon cancer incidence is rising in low‐ and middle‐income countries (LMICs), where resource limitations and cost often dictate treatment decisions. In this study, we evaluate the cost‐effectiveness of adjuvant chemotherapy for high‐risk stage II and stage III colon cancer treatment in South Africa (ZA) and illustrate how such analyses can inform cancer treatment recommendations in a LMIC. METHODS: We created a decision‐analytic Markov model to compare lifetime costs and outcomes for patients with high‐risk stage II and stage III colon cancer treated with three adjuvant chemotherapy regimens in a public hospital in ZA: capecitabine and oxaliplatin (CAPOX) for 3 and 6 months, and capecitabine for 6 months, compared to no adjuvant treatment. The primary outcome was the incremental cost‐effectiveness ratio (ICER) in international dollars (I$) per disability‐adjusted life‐year (DALY) averted, at a willingness‐to‐pay (WTP) threshold equal to the 2021 ZA gross domestic product per capita (I$13,764/DALY averted). RESULTS: CAPOX for 3 months was cost‐effective for both patients with high‐risk stage II and patients with stage III colon cancer (ICER = I$250/DALY averted and I$1042/DALY averted, respectively), compared to no adjuvant chemotherapy. In subgroup analyses of patients by tumor stage and number of positive lymph nodes, for patients with high‐risk stage II colon cancer and T4 tumors, and patients with stage III colon cancer with T4 or N2 disease. CAPOX for 6 months was cost‐effective and the optimal strategy. The optimal strategy in other settings will vary by local WTP thresholds. Decision analytic tools can be used to identify cost‐effective cancer treatment strategies in resource‐constrained settings. CONCLUSION: Colon cancer incidence is increasing in low‐ and middle‐income countries, including South Africa, where resource constraints can impact treatment decisions. This cost‐effectiveness study evaluates three systemic adjuvant chemotherapy options, compared to surgery alone, for patients in South African public hospitals after surgical resection for high‐risk stage II and stage III colon cancer. Doublet adjuvant chemotherapy (capecitabine and oxaliplatin) for 3 months is the cost‐effective strategy and should be recommended in South Africa.