Daniel Augusto Nunes de Lima, Fernando Castilho Pelloso, Elton da Cruz Alves Pereira, Maria Dalva de Barros Carvalho, Camila Wohlenberg Camparoto, Helena Fiats Ribeiro, Kely Paviani Stevanato, Deise Helena Pelloso Borghesan, Isabella Morais Tavares, Márcia Edilaine Lopes Consolaro, Roberto Kenji Nakamura Cuman, Vlaudimir Dias Marques, Ana Carolina Jacinto Alarcão, Constanza Pujals, Raíssa Bocchi Pedroso, Sandra Marisa Pelloso
Background: Breast cancer is the primary cause of cancer-related deaths among women globally, with a particularly high incidence in low- and middle-income nations. In Brazil, disparities in access to diagnosis and treatment contribute to worse clinical outcomes, particularly in regions with a lower Human Development Index (HDI). This study evaluated the association between the delay between diagnosis and treatment initiation, and clinical outcomes of breast cancer across various Brazilian regions. Methods: This observational study utilized publicly available secondary data from the Department of Informatics of the Unified Health System (DATASUS), collected between 2013 and 2023. Data included age group, treatment type (surgery, chemotherapy, radiotherapy), and delay between diagnosis and treatment initiation (≤30 days, 31–60 days, >60 days). Regional disparities were analyzed according to the HDI. Statistical analyses were performed using GraphPad Prism 8.0.1, applying Pearson’s correlation coefficient (r) and linear regression (R2) to assess associations between treatment delay and the number of cases or deaths. Results: Radiotherapy demonstrated the most significant negative correlation (r = −0.6624), and delays exceeding 60 days were consistently linked to poorer outcomes. In regions with lower Human Development Index (HDI), specifically the North and Northeast, longer treatment delays were observed, alongside a stronger correlation between delayed initiation of treatment and increased mortality. Conversely, shorter delays (30 days or less) demonstrated a weaker or absent correlation with improved outcomes. This suggests that other critical factors, such as the stage of cancer at diagnosis, the quality of care provided, and the consistency of treatment, are also significant determinants. Conclusions: Delays in treatment, particularly for radiotherapy and surgery, adversely affect breast cancer outcomes in Brazil. This impact is more pronounced in areas with lower Human Development Index (HDI), underscoring the critical need for targeted regional public policies. Such policies are essential to guarantee prompt diagnosis and treatment, thereby mitigating inequalities and enhancing survival rates.