The Risk of Breast Cancer Following Ovarian Cancer in Women With a Pathogenic Mutation in BRCA1 or BRCA2

Document Type

Conference Proceeding

Publication Date

2-2026

Publication Title

International Journal of Gynecological Caner

Abstract

Introduction/Background BRCA carriers face a high risk of developing both breast and ovarian (or fallopian tube) cancer. Among BRCA carriers with a diagnosis of ovarian cancer, it is not clear whether risk-reducing mastectomy or surveillance should be offered following completion of their cancer treatment. The aim of our study was to assess the risk of breast cancer in BRCA carriers after a diagnosis of ovarian cancer. Methodology This was a matched, case-control analysis of women carrying a pathogenic (or likely pathogenic) mutation in BRCA1 or BRCA2. Cases were women with a prior ovarian (or fallopian tube) cancer diagnosis, and controls were women without ovarian cancer. Each case was matched to one control based on year of birth, age at baseline questionnaire, BRCA gene, and country of residence. The 15-year cumulative risk of breast cancer was estimated using Kaplan-Meier test and Cox proportional hazards regression. Results A total of 1,482 BRCA carriers were eligible for inclusion: 1,300 BRCA1 and 182 BRCA2 carriers. There were 741 carriers with a prior ovarian cancer diagnosis and 741 carriers without. Breast cancer was diagnosed in 169 (22.8%) controls and in 33 (4.5%) cases (P< 0.0001), over a mean follow-up of 4.8 years (range 0.1—22.7) and 5.0 years (range 0.1—22.0), respectively. The mean age at breast cancer diagnosis was significantly lower in women without a history of ovarian cancer (53.3 vs. 57.5 years; P = 0.02). The 15-year cumulative incidence of breast cancer was 47.2% for controls compared to 12.2% for cases (P< 0.0001). The hazard ratio for breast cancer, after an ovarian cancer diagnosis, was 0.18 (95%CI 0.12-0.27; P< 0.0001). Conclusion BRCA carriers have a relatively low risk of developing breast after ovarian cancer. Risk-reducing mastectomy should not be routinely recommended but might be a consideration for long-term survivors without a recurrence. MRI surveillance and/or mammography is a realistic alternative.

Volume

36

Issue

2 Suppl 1

First Page

103142

Comments

ESGO (European Society of Gynaecological Oncology) 2026 Congress, February 26-28, 2026, Copenhagen, Denmark

Last Page

103142

DOI

10.1016/j.ijgc.2025.103142

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