Cause-specific mortality in reproductive-age breast cancer patients: A competing risk approach

Background: Breast cancer (BC) is a leading cause of mortality among women, particularly those in the reproductive age (15-49 years). Objective: This study aims to examine the survival outcomes of female BC patients in reproductive age groups using a competing risk approach, with a focus on identifying significant determinants of BC-specific mortality and mortality due to other causes. Materials and methods: This study utilized data from the Surveillance, Epidemiology, and End Results (SEER) database. The analysis included women diagnosed with breast cancer within reproductive age groups. The Cumulative Incidence Function (CIF), cause-specific hazard, and Fine-Gray subdistribution hazard models were employed to estimate the impact of potential determinants on BC-specific and other-cause mortality. Results: A total of 67063 patients were included in the study. The cumulative incidence of breast cancer-specific mortality and other cause mortality at 5 years was 4.8% and 0.95%, respectively. Age at diagnosis, race, tumor stage, and hormone receptor status were significant predictors of breast cancer-specific mortality. The Fine-Gray model revealed that younger age (15-39 years), advanced tumor stage, and negative hormone receptor status were associated with higher hazards for breast cancer mortality (p<0.05). Conclusion: The study highlights the importance of using a competing risk model to evaluate the cumulative incidence of prognostic factors in breast cancer patients of reproductive age, especially when competing clinical risks are present. These findings can guide personalized treatment strategies based on individual risk profiles.