Socio-Demographic Inequalities in Diagnostic Delays of Breast Cancer: A Multistage Time-to-Diagnosis Analysis

Background/Objectives: Introduction: Breast cancer remains a leading cause of cancer morbidity and mortality among women, and timely diagnosis is critical for improving outcomes. Organized screening programs strive to function efficiently, with minimal delays; however, evidence indicates that longer waiting times may be present at different stages of the diagnostic process. Few studies have evaluated how socio-demographic, reproductive, lifestyle, and clinical characteristics may influence diagnostic timeliness in a regional screening context. Materials and Methods: We retrospectively analyzed data from 240 women who underwent breast biopsy following abnormal screening assessment, out of 24,000 patients enrolled in a regional breast cancer screening program conducted in Northeastern and Southeastern Romania. Diagnostic timeliness was observed across three consecutive intervals of the screening pathway: mammography to biopsy (T1), biopsy to histopathological confirmation (T2), and cumulative presentation-to-diagnosis time (T3). Baseline population characteristics were described, subgroup comparisons performed, and multivariable regression models applied to identify independent predictors of diagnostic delay and to explore interaction effects at different stages of the screening process. Results: The interval between mammography and biopsy accounted for the most substantial waiting times (T1 median 24 days). The cumulative time to diagnosis (T3) reached a median of 32 days. Territorial inequalities were the strongest determinant of delay: rural patients experienced approximately five additional days before histopathological confirmation compared with urban patients (p = 0.003). Social vulnerability further contributed to prolonged T1 and T3 intervals, while lifestyle, reproductive, and anthropometric factors showed only minor or inconsistent associations. Interaction analyses revealed that delays linked to rural residence were most pronounced among younger women, an age group at higher risk for aggressive subtypes such as triple-negative breast cancer. Conclusions: In our findings, regional background and social vulnerability outweighed individual risk factors in shaping total diagnostic time. These results support the careful monitoring of interval-specific performance to strengthen equitable access to biopsy among vulnerable populations, where the effectiveness of early breast cancer detection is often challenged.