Survival and medical costs of melanoma patients with subsequent cancer diagnoses: A South Korean population‐based retrospective cohort study

AIM: Subsequent cancers (SCs) after melanoma diagnosis further increases the risks of mortality and medical costs. This population‐based analysis aimed to evaluate risk factors for SC, mortality, and medical costs of melanoma patients with SC. METHODS: A retrospective cohort analysis was conducted using a nationwide claims database during 2002‐2017 in South Korea. SC was defined as having other types of cancer diagnoses other than subsequent melanoma during‐up to 5 years after melanoma diagnosis. Melanoma patients were divided into patients with and without SC, and the overall and subgroup survival rates, the risk of developing SC, and the total medical costs were analyzed using a Kaplan–Meier method and regressions. RESULTS: A total of 3740 melanoma patients were included in the analysis (mean age, 62.3 ± 15.4 y; 47.2% men), and 2273 patients (1157 within 2 months, 756 after 2 months of melanoma diagnosis) had SC. Higher Charlson comorbidity index score and male sex significantly increased the risk of developing SC. Five‐year survival rate and cumulative medical costs were 62.3% (95% confidence interval [CI], 60.8‐63.9) and $21,413, respectively, in all patients. Patients with SC diagnosed after 2 months showed the lowest survival rate of 47.8% (95% CI, 44.3‐51.4) and the highest costs of $27,081, showing a mortality hazard ratio of 1.65 (range, 1.46‐1.86) and a cost ratio of 1.189 (range, 1.112‐1.271) compared with those without SC. CONCLUSION: This study presented survival outcomes and medical costs in melanoma patients and confirmed that SC after the first diagnosis of melanoma significantly increased disease burden in terms of mortality and medical costs.