Abstract PO1-09-12: Cancer health disparities among patients with early-stage estrogen receptor-positive (ER+) breast cancer treated in public or private practices in Brazil

Abstract Background Cancer registries in Brazil are deficient and data about patients’ profiles and cancer treatment patterns are scarce in the country. Moreover, while 30% of population has access to private insurance, almost 70% of population uses publicly health services. The objective of this work was to describe the sociodemographic and clinicopathological characteristics of women with early-stage ER+ breast cancer on adjuvant ET in different regions of Brazil, and to describe treatment patterns for this disease according public and private institutions. Methodology: We performed a real-world data analysis in different institution regions of Brazil. Women with a history of early-stage ER+ invasive carcinoma of the breast on adjuvant endocrine therapy for at least 6 months were invited to participate of this study in 12 centers in four different regions in Brazil. Demographic and clinicopathologic information was retrieved from medical records. In order to compare healthcare insurance type, we considered patients who were treated under the Brazilian public health system as publicly insured, and women who had private insurance or paid for their treatment as privately insured. High education level was defined by completed high school. Data collection was done with RedCap software. Qualitative variables were compared between groups using the Chi-square or exact Chi-square test and for quantitative variables the non-parametric Mann-Whitney test was used. P 0.05 was considered significant. Analyzes were performed in SAS 9.4; Results: From June 2021 to May 2023, a total of 461 women with ER+, early BC, were included in this analysis. A total of 233 (50.6%) came from private institutions, the mean age was 56.02 years (range 22-93), 47.69% were non-white, 61.3% were post-menopause, 61.7% lived with a partner, and 76.2% were highly educated and 66.81% had comorbidities. Tumor staging at diagnosis was classified as III, II and I respectively in 21.26%, 43.17% and 35.57% of all cases. Regarding treatment received, 62.4% of patients underwent lumpectomy, 32.2% had axillary dissection, 67.6% received (neo)adjuvant chemotherapy, 45.2% were on aromatase inhibitors and 14.19% were on ovarian function suppression plus ET . Median duration of ET use was 2.78 years (range 6 months- 9.61 years). Publicly health insurance was associated significantly associated with younger age at diagnosis ( 60 yo), premenopausal status, to live alone, lower educational level, more advanced tumors, prior mastectomy, prior axillary dissection, prior neo-adjuvant chemotherapy, prior radiotherapy, lower use of aromatase inhibitors, ovarian function suppression plus ET, and CDK4/6 inhibitors, while higher use of concomitant medications. Conclusion: The study shows significant health disparities among women with early-stage ER+ breast cancer treated in private versus public institutions in Brazil. Importantly, despite having more advanced tumors, women in public institution had less access to ovarian suppression, CDK4/6 inhibitors and were treated with more aggressive surgical procedures. A deep discussion involving government, lawmakers, health care providers and patients should be conducted to try to decrease the described disparities. Patient’s characteristic and patterns of treatment among patients with estrogen receptor-positive breast cancer on adjuvant therapy according to health insurance in Brazil ALND: axillary lymph node dissection; CDK4/6i: CDK4/6 inhibitors; ET: endocrine therapy; OS: ovary suppression. Citation Format: Romualdo Barroso-Sousa, Daniele Assad-Suzuki, Danielle Santos, Fernanda Moura, Sulene Oliveira, Anna Luiza Galvão, Bruno Souza, Amanda Castro, Monalisa Andrade, Andrea Shimada, Yuri Beckedorff, Maria Cristina Magalhães, Cristiano Souza, Carlos Paiva, Heloísa Resende, Daniela Pereira, Angelica Rodrigues, Daniela Rosa. Cancer health disparities among patients with early-stage estrogen receptor-positive (ER+) breast cancer treated in public or private practices in Brazil abstract. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO1-09-12.