10-year opportunistic mammographic screening scenario in Brazil and its impact on breast cancer early detection: a nationwide population-based study

Background Mammographic screening has been used to reduce breast cancer mortality worldwide and remains the main modality for the early detection of this disease. Women from low-and middle-income countries still lack access to periodic mammograms and efficient health care. This cross-sectional study aimed to explore opportunistic mammographic coverage in Brazil, while con -sidering the privately insured population and its association with early breast cancer (EBC) detection.Methods Data on population, gross domestic product (GDP), number of mam-mograms performed under the Sistema Unico de Saude (SUS) public health system or private system, and women diagnosed with early-stage breast cancer from 2010 to 2019 were retrieved from publicly available databases.Results A total of 39 555 636 mammograms with an average of 3 955 564 +/- 395 704 mammograms were obtained per year from 2010 to 2019 in Brazil. Most ex-aminations (58.6%) were performed in the target population (50-69 years old), while 32% were performed in women aged 40-49, and 9.4% were performed in women <40 years or >70 years of age. The 10-year mammogram coverage was 30.6% in the target population and 24.8% in the population aged 40-49 years, with significant variation across states and municipalities. The overall EBC de-tection rates in Brazil were 30.6% in populations aged 50-70 and 24.8% in those aged 40-50 years. We observed a positive correlation between coverage and EBC detection rate (r=0.68; P=0.0001 (50-70 years) and r=0.75; P<0.0001 (40-50 years)). According to the GDP, the municipalities with higher GDP per capita had higher mammogram coverage (P<0.0001).Conclusions The coverage of mammographic screening for women under the SUS is far below the international guidelines. Additionally, a significant num -ber of mammograms have been performed in non-target populations. This sce-nario reflects the problematic screening programs in developing countries and reflects low rates of EBC diagnosis. As Brazil is a continental country with het-erogeneous socioeconomic indicators, we observed significant variations in the number of mammograms performed by age groups when separated by states and municipalities. Even when considering supplemental health system cov-erage, municipalities with higher GDP per capita were associated with higher mammogram coverage.