BC remains a significant burden on the Brazilian public healthcare system. The findings of the current study indicate that, over an analyzed period of 6 years, there were no significant variations in the incidence of BC among both White women and their Black counterparts. A comparative analysis between the two racial groups revealed considerable disadvantages related to sociodemographic and clinicopathological factors for Black women compared to White women. These differences may explain the significant 3.83-fold higher annual increase in mortality among Black women compared to White women over a period of 20 years.
Kaur et al. [14] studied data from the United States in the period spanning 2004 to 2017 and found a surge in BC incidence rates, particularly among non-Hispanic Black women. The most significant increases were observed in non-Hispanic Black women in lower-poverty areas (0.8%), rural areas (1.2%), and in all regions except the West (0.8–1.0%). Non-Hispanic Black women also experienced marked rises in early and advanced stage BC subgroups. Similarly, Hispanic women had notable increases, including in areas with higher poverty (0.6–1.2%) and in the West (0.8%), for early and advanced diseases. These results highlight the escalating burden of BC in specific subpopulations, some of which already face disproportionately high mortality rates.
Makhetha et al. [15] examined the global increase in BC incidence, particularly in low- and middle-income countries, and specifically studied hereditary BC patients in South Africa’s KwaZulu-Natal province. The data collected from 2011 to 2021 included 645 patients, with significant increases in annual new cases, particularly among Black individuals. Black patients were diagnosed approximately 10 years earlier than White and Indian patients, with TNBC accounting for 20.3% of hereditary cases, disproportionately affecting Black individuals. Pathogenic BRCA1/2 sequence variants were identified in 10.4% of all patients, with a higher prevalence among Black and Indian patients.
The Brazilian National Health Survey of 2013 revealed disparities in mammography rates, with 66.2% of White women, 54.2% of Black women, and 52.9% of mixed-race women having undergone screening. The educational level also influenced mammography rates, with college-graduated women having higher coverage at 80.9% compared to 50.9% for those with incomplete schooling [16]. Additionally, disparities in educational attainment were observed between White and Black/mixed-race populations, as White women had almost double the access to college graduation compared to Black and Mixed-race women [17]. These findings suggest that White women may have better access to BC screening programs. This is supported by data collected from HBCRs in this study, which showed a significantly higher proportion of women with lower education levels and more advanced disease at diagnosis in the Black population compared to the White population.
Data from national inquiries in 2012 and 2022 show that Black and Mixed-race populations primarily reside in Brazil's North and Northeast regions, which have lower HDI scores compared to other regions [18]. Residents in these less developed areas may face challenges in accessing healthcare services, preventive screenings, and adequate BC treatments. The 2023 annual report on BC statistics from the Brazilian National Cancer Institute revealed significant disparities in mammography availability, with only 38.7% of women in the Northern region undergoing screening compared to 67.9% in the Southeastern region [19, 20]. Analysis in this study found that 56.4% of Black women with BC resided in these less developed regions, contrasting with 14.1% of White women, highlighting regional and structural imbalances contributing to differing incidence and mortality rates between the ethnic groups.
The current analysis of breast cancer-specific mortality rates using AAPC found a strikingly higher increase in mortality for Black women compared to White women. That said, the racial disparities in healthcare outcomes could be influenced by socioeconomic factors and potential implicit bias among healthcare professionals, impacting communication, clinical investigation, and treatment decisions for vulnerable patients [21]. In Brazil, dissatisfaction with healthcare and hospitalization was observed in 12.2% of White patients and 17.4% of Black and Brown patients. Black or Brown individuals seeking healthcare were twice as likely as White individuals to go untreated [22]. International literature does not strongly support biological plausibility for these differences. Studies have shown that Black individuals face higher mortality rates from certain tumors, even after considering factors like stage and tumor characteristics, suggesting that delayed or incomplete treatment may contribute to these disparities [23]. Additionally, racial disparities in diagnosis, treatment, and survival persist across different socioeconomic statuses and healthcare access [24].
The time from BC diagnosis to treatment onset significantly affects survival, with an increased risk of death if treatment is delayed beyond 60 days [25]. A study in Brazil from 2019–2020 found that over half of BC patients experienced delays of more than 60 days before starting oncology treatment, with age and travel distance to treatment sites influencing the likelihood of delay [26]. Another study in the city of Juiz de Fora in Brazil showed statistical differences in BC incidence between White and Black women. Most women treated in the private healthcare system were White and experienced shorter waiting times between diagnosis and treatment onset, averaging 52 days compared to 82 days in the public healthcare system [27]. These findings may contribute to the increasing BC mortality rate and the higher mortality rates among Black women compared to White women in Brazil. Nonetheless, further research is needed to better understand this correlation.
Representing around 20% of Brazil's total population with reliable death registry notification, an epidemiological study in São Paulo from 2000 to 2017 found a decrease in BC mortality rates among White women, but an increasing trend among Black women in this region [28]. In contrast, the United States observed a 43% decline in BC mortality rates from 1989 to 2020, with an annual decrease of 1.9% from 1998 to 2011, and 1.3% from 2011 to 2020 [9]. Notably, while BC mortality rates were progressively lower in the United States, a persistent racial disparity was observed between Black and White women. This disparity is linked to systemic racism in cancer care, encompassing issues such as disparities in screening quality, longer intervals between mammograms and follow-up of abnormal findings, and substandard treatment. Biological factors also contribute to racial disparities, including a higher incidence of hormone receptor-negative BC in Black women, known for lower survival rates. Despite these intrinsic factors, Black women continue to exhibit higher mortality rates, suggesting difficulties in accessing more effective treatments for HER2-positive and TNBC [29–33].
The recently published nationwide cohort study performed by Lemos et al. [34] focused on women receiving breast cancer treatment within Brazil's public healthcare system, Sistema Único de Saúde. The study employed a comprehensive approach by linking administrative and mortality information systems, enabling the assessment of survival outcomes based on race or skin color. The results indicated a significant disparity in 5-year survival probability and all-cause mortality risk between Black and White women, with the former experiencing a notably lower survival rate and higher risk of all-cause death. Even after adjusting for covariates, including hormone therapy, the elevated risk for Black women persisted.
In 2023, the American Cancer Society released an updated report on racial, ethnic, socioeconomic, and geographic inequalities in cancer occurrence and outcomes, as well as provided insights into initiatives that have effectively mitigated these disparities. The report revealed significant disparities in risk factors, diagnosis stages, care provision, survival, and cancer mortality based on race/ethnicity, educational attainment, and metropolitan status. Black and American Indian/Alaska Native individuals faced persistently higher cancer mortality rates, especially among those with 12 years or fewer of education[35].
The present study demonstrates several notable strengths, including its population-based design encompassing extensive national coverage and the comprehensive analysis of a substantial time period capturing incidence and mortality rates recorded in national databases. Nonetheless, it is imperative to consider certain methodological constraints that may impact the interpretation of the data. Firstly, the accuracy and reliability of the data collected from registries and information systems may exhibit regional variability. Secondly, inherent limitations associated with observational studies, such as the inability to establish causality and account for unmeasured variables, should be considered when interpreting the findings. Furthermore, the absence of information on lifestyle factors, socioeconomic status, health insurance, screening practices, and family history could potentially influence the outcomes of the disparity analyses among the racial groups. Lastly, the utilization of Population-Based Cancer Registries (PBCRs) was based on the availability of female population data categorized by race. Nevertheless, the calculation of adjusted incidence rates was unfeasible due to the unavailability of race- and age-group-stratified population data for the PBCRs featured in the study.
In conclusion, the current analysis of epidemiological data on BC by race from national population-based public databases indicates marked differences in the pattern of cancer incidence and mortality according to race. Furthermore, there was a notable frequency of Black women in regions with limited access to early detection exams. These women often exhibit lower educational levels and are more susceptible to advanced-stage diagnoses, leading to reduced access to timely diagnosis and appropriate treatment, ultimately contributing to lower survival rates. This systemic issue within the Brazilian healthcare system has broader implications, presenting a significant national challenge that affects the sustainability of the healthcare system, particularly within the context of the Brazilian public health system. The inadequacy of resources for providing comprehensive care to Brazilian women diagnosed with BC, as indicated by the findings, emphasizes the critical need for research that informs public health policies, facilitating more effective allocation of resources towards screening, prevention, and cancer treatment.