Clinicopathologic Features and Management Patterns of Synchronous Bilateral Breast Cancer: A Single-Institution Review

Authors

• Victor Magano Castro, Corewell Health West Resident
• Gerald P. Wright, Corewell Health West
• Jessica Thompson, Corewell Health West

Document Type

Conference Proceeding

Publication Date

10-2025

Abstract

Introduction: Synchronous bilateral breast cancer (BBC) occurs in 1-3% of cases. Identifying contralateral disease at diagnosis is critical. Data's limited on BBC's. We sought to characterize clinicopathologic features, detection patterns, and management approaches.

Methods: A retrospective analysis was conducted for stage 0-III BBC patients treated at our institution from 2019-2023. Synchronous BBC was defined as cancers diagnosed within 6-months. Patients with prior metachronous breast carcinoma or stage IV disease were excluded.

Results: A total 116 patients met inclusion criteria. The median age was 63 (30-88). Genetics was performed in 91 patients; 14 had pathogenic variants. BBC detection was concurrent in 62 (53.4%) via mammography, screening-MRI, and punch biopsy. The remaining 54 (46.6%) were diagnosed non-simultaneously, by diagnostic-MRI or as occult findings. Tumor characteristics included 9 bilateral ductal carcinoma in situ (DCIS), 61 bilateral invasive carcinoma, and 46 DCIS/invasive carcinoma. Among 61 with bilateral invasive disease, receptor subtype was concordant in 49; 48 with bilateral hormone receptor-positive, HER2-negative disease and 1 with triple-negative disease. Neoadjuvant therapies were administered to 14 patients. Surgery included bilateral mastectomy, bilateral lumpectomy, and mastectomy/lumpectomy. Among 17 who underwent MRI, 53 had bilateral mastectomy compared to 17 of the 40 who didn't have an MRI (p=0.0054). During this period, there were 7 recurrences. Disease-free survival (DFS) in the BBC cohort was 92.2%, compared to unilateral breast cancer cohort (DFS 94.3%, p=0.51).

Conclusion: Synchronous BBC is often receptor subtype concordant and managed diversely. These findings contribute to a better understanding of clinicopathologic characteristics, detection patterns, and treatment approaches.

Comments

ACS (American College of Surgeons) Clinical Congress, October 4-7, 2025, Chicago, IL

Recommended Citation

Castro VM, Wright GP, Thompson J. Clinicopathologic features and management patterns of synchronous bilateral breast cancer: A single-institution review. American College of Surgeons Clinical Congress (ACS), 2025 Oct; Chicago, IL.