Type 2 Diabetes Mellitus and Advanced Stage at Breast Cancer Diagnosis: A Retrospective Study from Constantine

Introduction: Type 2 diabetes mellitus (T2DM) and breast cancer (BC) represent two major public health challenges with increasing prevalence, particularly in Algeria. These conditions share common risk factors and interconnected pathophysiological mechanisms that may influence disease onset and progression. Methods: We conducted a retrospective study using data prospectively collected from hospital registries to estimate the prevalence of T2DM–BC association among women with breast cancer in Constantine district. Clinical, biological, and therapeutic data were analyzed to identify diabetes-related common and specific risk factors. Results: The prevalence of T2DM among breast cancer patients was 17%. Mean age at cancer diagnosis was 62.0 ± 10.3 years, with 93% of patients aged over 50 years, predominantly postmenopausal. Overweight and obesity affected 81.5% of patients. Mean diabetes duration was 11.1 ± 8.3 years. Poor glycemic control (HbA1c > 7%) was observed in 61.4% of patients. Regarding diabetes treatment: 67.0% received oral antidiabetic drugs (OADs; 83.7% on metformin), 11.6% used lifestyle modifications alone, 11.6% combined OADs + insulin, and 9.6% used insulin alone. The majority of patients (88.8%) were diagnosed at advanced stages: IIIA (41.5%), IIIB (32.3%), and IV (15.0%). Conclusion and Future Perspectives: This first Algerian study confirms the significant prevalence of T2DM-BC association and identifies modifiable risk factors. These findings highlight the importance of a multidisciplinary approach integrating oncologists and endocrinologists to optimize management of this complex comorbidity. Prospective studies are needed to evaluate impact on mortality and survival.