Cancer in Young Women: Late-Stage Breast Cancer Registry Analysis of a 24-Year Nationwide Retrospective Cohort of 52,734 Patients in Brazil (CLARA Study).

BACKGROUND: Younger patients are not included in routine screening for breast cancer (BC) and can have delays in diagnostic evaluation. Particularly in Brazil, approximately 40% of women with breast cancer are diagnosed with late stage disease (III or IV), emphasizing persistent barriers to timely diagnosis and specialized care by the public healthcare coverage (The Brazilian Unified Health System; Sistema Único de Saúde; SUS). This study aims to estimate the frequency of late-stage BC (stages III or IV) at diagnosis among young women treated by (SUS) and identify associated sociodemographic and clinical factors. MATERIAL AND METHODS: Cross-sectional nationwide population-based study conducted to analyze data from the national Hospital Cancer Registry, including women aged 15 to 39 years diagnosed with BC, between 2000 and 2023. RESULTS: Nearly half (48.2%) of young women with breast cancer in Brazil are diagnosed at late stages (III-IV). In the multivariate analysis, self-reported Black or brown race (OR 1.18; 95%CI, 1.12-1.25), education < 9 years (OR 1.22; 95%CI, 1.15-1.29), absence of a partner (OR 1.09; 95%CI, 1.04-1.15), invasive carcinoma subtype of no special type (OR 1.16; 95%CI, 1.08-1.25) and referral by the public system (OR 1.31; 95%CI, 1.19-1.44) registered an independent association with late stage. CONCLUSION: Brazil faces a high rate of late-stage breast cancer diagnoses among young women and the independent predictors of late presentation emphasizes the impact of social and structural inequities on oncology care.