Diabetes Mellitus and Survival Outcomes in Women With Early-Stage Triple-Negative Breast Cancer: A Multicentre Population-Based Cohort Study From Saskatchewan

OBJECTIVE: Diabetes mellitus has been associated with worse outcomes in several malignancies, yet its impact on women with early-stage triple-negative breast cancer (TNBC) remains unclear. This multicentre population-based cohort study evaluated the association between diabetes and survival outcomes in women with TNBC treated with neoadjuvant and/or adjuvant (curative-intent) chemotherapy. METHODS: Adult women diagnosed with stages I to III TNBC in Saskatchewan, Canada (2010 to 2018), were identified. Patients were categorized by diabetes status. Overall survival (OS), disease-free survival (DFS), and invasive DFS were assessed using Kaplan-Meier methods, with multivariable Cox regression and inverse probability of treatment weighting (IPTW) to control for confounding factors. RESULTS: Among 357 eligible women, 36 (10%) had diabetes. With a median follow-up of 88 months, women with diabetes experienced significantly inferior 5-year OS (61% vs 83%) and DFS (56% vs 78%) compared with women without diabetes (p