Comparison of survival between unilateral and bilateral breast cancers using propensity score matching: a retrospective single-center analysis

Breast Cancer Res Treat. 2025 Jan 9. doi: 10.1007/s10549-024-07606-1. Online ahead of print.

Abstract

Purpose: The characteristics of patients with bilateral and unilateral breast cancer at the time of diagnosis or during follow-up have been compared, focusing on the differences in disease-free survival and overall survival between these groups.

Methods: A total of 1,947 patients diagnosed with invasive carcinoma were included in the study. 1876 ​​(96.4%) of our patients had unilateral and 71 (3.6%) had bilateral breast cancer. Among the bilateral breast cancer patients n = 47 were metachronous, while n = 24 were synchronous.

Results: SBBC, which had the lowest OS duration, showed a statistically significant difference compared to MBCC, similar to that observed in unilateral breast cancer (p = 0.027).

Conclusion: The fact that SBBC has the lowest survival rate despite more aggressive treatments should be considered a poor prognostic factor for survival on its own.

Keywords: Bilateral breast cancer; Breast Cancer; Metachronous bilateral breast cancer; Multivariate cox regression analysis with backward stepwise; Propensity score analysis; Synchronous bilateral breast cancer; Unilateral breast cancer.