Abstract PS1-05-28: Evaluating all-cause mortality and endocrine therapy tolerability with sodium glucose cotransporter-2 inhibitors in hormone receptor-positive breast cancer: A real-world analysis

Abstract Introduction: Endocrine therapy (ET) is central to treating hormone receptor-positive breast cancer (BC), but its side effects impact adherence and quality of life, especially in patients with metabolic dysfunction. Sodium-glucose cotransporter-2 (SGLT-2) inhibitors offer cardiometabolic benefits, potentially improving inflammation, glycemic control, and physical well-being. However, data on SGLT-2 use in BC patients is scarce. This study is the first to evaluate the real-world effects of SGLT-2 inhibitors on all-cause mortality and ET tolerability in BC patients. Methodology: We conducted a real-world analysis using the TrinetX database, which includes data from 184 million patients in 156 healthcare organizations, to identify BC patients on ET (letrozole, anastrozole, exemestane, tamoxifen) who received SGLT-2 inhibitors vs. those who did not. Patients were grouped by age (≤50 and ≥51 years as a surrogate for menopausal status. Primary outcome: all-cause mortality from the start of the index event, defined as the first day meeting BC diagnosis and ET use, with or without SGLT-2. Secondary endpoint: ET tolerability. Propensity score matching completed by TriNetX adjusted for confounders. Multivariate analysis yielded odds ratios and risk differences with 95% CI. Results: Among 1,136 BC patients ≤50 years, 568 were assigned to each group (SGLT-2 vs non-SGLT-2). For patients ≥51 years (n=28,600), each group included 14,300. Demographics across cohorts were comparable. No mortality benefit was seen in premenopausal patients. In postmenopausal women, SGLT-2 use reduced all-cause mortality—647/13,676 events (SGLT-2) vs 953/13,517 (non-SGLT-2) OR: 0.655 (0.591-0.726). In premenopausal patients, SGLT-2 reduced endometrial cancer risk RD: -0.018 (-0.029, -0.007) but increased diarrhea risk OR: 2.305 (1.078, 4.930). No significant differences were found in hot flashes, PE, DVT, depression, osteoporosis, joint pain, fatigue, nausea/vomiting, abdominal pain, or dizziness. Among postmenopausal patients, SGLT-2 reduced PE OR: 0.757 (0.605-0.948) and osteoporosis OR: 0.877 (0.784-0.981), but increased risks of depression OR: 1.153 (1.007-1.319), nausea/vomiting OR: 1.120 (1.001-1.253), diarrhea OR: 1.193 (1.058-1.345), and dizziness OR: 1.234 (1.103-1.380). No significant differences were found for hot flashes, DVT, EC, joint pain, fatigue, or abdominal pain. Conclusion: This analysis reveals novel evidence supporting the cardiometabolic potential of SGLT-2 inhibitors in hormone receptor-positive BC, particularly postmenopausal populations. These agents were linked to lower all-cause mortality and improved tolerance of specific ET-related effects. However, certain adverse risks require caution. Future prospective studies are essential to validate their role and safety in oncologic care. Citation Format: C. Jones, J. Michalek, E. Obomanu, Y. Arya, A. Syal, S. Haddad, V. Kaklamani, S. Shaikh. Evaluating all-cause mortality and endocrine therapy tolerability with sodium glucose cotransporter-2 inhibitors in hormone receptor-positive breast cancer: A real-world analysis abstract. In: Proceedings of the San Antonio Breast Cancer Symposium 2025; 2025 Dec 9-12; San Antonio, TX. Philadelphia (PA): AACR; Clin Cancer Res 2026;32(4 Suppl):Abstract nr PS1-05-28.