Abstract
BACKGROUND: Lung cancer is the leading cause of cancer-related mortality in Brazil, yet few studies have characterized real-world treatment pathways within Brazil’s private supplementary health sector, which covers nearly 25% of the Brazilian population. METHODS: We conducted a retrospective cohort study including patients with biopsy-confirmed lung cancer treated between 2020 and 2024 within the Hapvida NotreDame Intermédica system, the largest private health insurer in Brazil. Demographic, clinical, treatment, and cost data were extracted from structured administrative and electronic medical record databases. Descriptive statistics, Kaplan–Meier survival analysis, and cost estimations (in Brazilian reais, adjusted by IPCA) were performed. RESULTS: A total of 690 patients were identified. Median age at diagnosis was 67 years, and 56.4% were women. Stage IV disease was most common (35.7%), while 32.5% had missing stage documentation. Adenocarcinoma predominated (64.5%), and surgical resection was performed in 37.5% of patients. Chemotherapy was administered in 64.9%, mostly with palliative intent, and radiotherapy in 48.8%. Hospitalization occurred in 78.5% of patients, and 36.4% required ICU admission. Median survival was significantly longer for patients with early-stage disease and for those who underwent surgery. Median direct healthcare costs increased with advancing stage, ranging from R$19,544 in stage I to R$75,837 in stage IV, with hospitalizations and surgeries as main cost drivers. CONCLUSIONS: This large real-world cohort from Brazil’s private sector highlights the predominance of late-stage diagnoses, incomplete molecular testing, high rates of acute care utilization, and substantial costs associated with lung cancer. These findings complement previous Brazilian studies and underscore the need for earlier detection, expanded biomarker access, and cost-efficient strategies in supplementary healthcare systems. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12885-026-15702-2.