2788 - Sex-Based Disparities in Long-term Survival after Surgery for Stage I-III Hormone Receptor-Positive Breast Cancer
Presenter(s)
M. Liu1, Z. Ma1, Z. Wang2, J. Yuan3, A. Jiang3, H. Yuan1, B. Tian3, F. Wang3, Y. Xu3, J. Yu3, and D. Chen3; 1Cancer Center, Shandong University, Jinan, Shandong, China, 2Shandong Second Medical University, Jinan, Shandong, China, 3Shandong Provincial Key Laboratory of Precision Oncology, Shandong Cancer Hospital and Institute, Shandong First Medical University and Shandong Academy of Medical Sciences, Jinan, Shandong, China
Purpose/Objective(s):
Hormone receptor-positive (HR+) breast cancer accounts for more than 90% of male cases, and its breast cancer-specific mortality risk can persist beyond 20 years post-diagnosis. However, the long-term survival differences and the mediators of the disparity between male and female patients have not been fully studied. Our objectives were to quantify sex-based differences in cancer-specific and overall mortality among patients with non-metastatic HR+ breast cancer over a 20-year follow-up period and to identify key clinical and demographic factors that mediate these disparities. By addressing these questions, we aim to enhance understanding of the factors contributing to the observed disparities and to inform strategies for improving outcomes in male breast cancer patients.Materials/Methods:
Using the Surveillance, Epidemiology, and End Results (SEER) database (1990 to 2011), we identified 150,740 patients (1,075 men and 149,665 women) with stage I to III HR+ breast cancer who underwent surgery. Univariate adjusted and multivariate sequential Cox proportional hazards models were used to assess the sex-disparity on breast cancer-specific survival (BCSS) and overall survival (OS) and the contribution of demographics, tumor characteristics, and treatment factors to this disparity.Results: Male patients presented at older age (65.4 vs. 60.2 years), higher stage (63.4% vs. 44.4% of stage II-III), larger tumor size (41.2% vs. 29.0%), higher tumor grade (30.8% vs. 21.6% of Grade III-IV), and received radiotherapy less often (27.6% vs. 57.1%) compared with female patients. The 20-year BCSS rate was 67% in men vs. 82% in women, and the 20-year OS rate was 27% vs. 51% (both P<0.001). Stage at diagnosis explained 38.8% of the excess cancer-specific mortality risk (adjusted hazards ratio [aHR], 1.60; 95% CI, 1.40-1.82), and age at diagnosis accounted for 33.5% of the excess overall mortality risk (aHR, 1.70; 95% CI, 1.58-1.83) among male patients compared with female patients. Other notable contributors included radiotherapy and tumor grade.
Conclusion: Among non-metastatic HR+ breast cancers, men generally exhibit inferior long-term BCSS and OS. The factors of advanced disease stage and older age at diagnosis are prominent, underscoring the critical importance of early detection and timely diagnosis to improve prognostic outcomes for male breast cancer patients.