Regional divergence in female cancer mortality in Brazil signals the unequal pace of the cancer transition

The cancer transition framework describes the shift from infection-related cancers, such as cervical cancer, to cancers more commonly observed in high human development settings, such as breast cancer, as societies develop. Brazil, with marked regional disparities in health and socioeconomic indicators, offers a unique context to analyze how this transition unfolds unevenly across subnational regions. This study aimed to describe and compare levels and temporal trends in age-standardized mortality rates for breast and cervical cancer across Brazilian macroregions from 1980 to 2021, and to contextualize these patterns in relation to global Sociodemographic Index (SDI) group profiles. We conducted an ecological analytical study with time series analysis of breast (C50) and cervical cancer (C53) mortality in Brazil from 1980 to 2021. Data were retrieved from the Global Burden of Disease (GBD) study, stratified by the five Brazilian macroregions and compared with global Sociodemographic Index (SDI) groups. We applied Joinpoint regression models to identify inflection points in mortality trends and estimated the Annual Percentage Change (APC) with 95% confidence intervals (CIs). Age-standardized mortality rates from GBD are presented with their corresponding 95% uncertainty intervals (UIs). Breast cancer mortality rates were highest in Brazil’s Southeast (18.97 deaths/100,000) and South (18.20), with lower but rising rates in the North (11.08). Cervical cancer mortality was highest in the North (18.92) and lowest in the Southeast (9.83). Joinpoint regression revealed three trend periods for breast cancer (1980–1995, 1995–2014, 2014–2021) and two for cervical cancer (1980–1997, 1997–2021). While breast cancer mortality declined in the Southeast and South until mid-2010s and then rose again, the North and Northeast showed persistent increases. Cervical cancer mortality declined nationwide, but more slowly in the North and Northeast. Comparisons with SDI groups showed that the South and Southeast align with higher-SDI profiles, whereas the North and Northeast resemble lower-SDI groups. Breast and cervical cancer age-standardized mortality rates in Brazil follow divergent trajectories consistent with the cancer transition model, but regional inequalities shape their pace and intensity. While wealthier regions display mortality patterns consistent with contexts characterized by stronger health system capacity, as reported in the literature, less developed regions remain burdened by preventable cervical cancer and rising breast cancer mortality. Targeted, equity-oriented policies are essential to address structural disparities in prevention, screening, and treatment.