Study: Breast cancer risk after ovarian cancer in women with BRCA mutations
Women who have an inherited mutation in BRCA1 or BRCA2 have a higher lifetime risk of developing breast and ovarian cancer compared to women without these mutations. This study found that after being diagnosed with ovarian cancer, women with a BRCA1 or BRCA2 mutation have a relatively low risk of developing breast cancer. (posted 5/18/2026)
RELEVANCE
Most relevant for: People with a BRCA1 or BRCA2 mutation who have had ovarian cancer.
Relevance: Medium-High
Strength of Science: Medium-High
Research Timeline: Post Approval
What is this study about?
This study looked at women with a or mutation to measure the risk of developing breast cancer after an ovarian cancer diagnosis.
Why is this study important?
Current guidelines outline options for breast cancer risk management for women with a or mutation. The guidelines recommend annual screening with both and . Preventive surgery has been shown to reduce death from breast cancer and improve life expectancy among and mutation carriers who have not had cancer.
The guidelines also include information about risk-reducing mastectomy as an option for high-risk women after discussion with their doctor about the benefits, risks, costs and timing of surgery.
Current guidelines do not provide specific guidance for high-risk women who have previously been diagnosed with ovarian cancer. Some women prefer annual breast scans, while others consider a preventive surgery to remove both breasts (a mastectomy).
Study findings
It is not well-known whether risk-reducing mastectomy benefits or mutation carriers after an ovarian cancer diagnosis. To help guide decision-making for these women, researchers looked at how often breast cancer occurred after an ovarian cancer diagnosis in women with a BRCA1or mutation.
The study followed 960 women with a or mutation who had ovarian cancer.
- 814 had a mutation
- 146 had a mutation
41 women (4.3%) developed breast cancer during follow-up of almost 5 years.
Overall, about 1 out of 100 (1%) women per year developed breast cancer after ovarian cancer. This is lower than the 4 out of 100 (4%) per year risk in women with a or mutation who have not been diagnosed with ovarian cancer.
The estimated risk of breast cancer after an ovarian cancer diagnosis was:
- 4.4% at 5-year follow-up.
- 8.9% at 10-year follow-up.
- 11.5% at 15-year follow-up.
What does this mean for me?
Women with an inherited or mutation who have been diagnosed with ovarian cancer have to make decisions about managing their breast cancer risk. To date, guidelines on risk management for mutation carriers have not addressed the unique circumstances and risks for a breast cancer diagnosis in this population.
This small study found that the chance of developing breast cancer after ovarian cancer was about 1% per year, which was lower than expected. This may partly be due to the effects of surgery to treat ovarian cancer and/or treatment, but this study did not directly examine those factors. More research is needed to understand whether PARP inhibitors used to treat ovarian cancer may also lower the risk of breast cancer.
It is also important to note that these results are group averages from one study that followed participants for about 5 years. Individual breast cancer risks may differ by age, whether the mutation is in the or gene, past breast health history, and ovarian cancer treatments received.
The relatively low risk of breast cancer among women with a or mutation after an ovarian cancer diagnosis may help healthcare professionals develop more specific guidelines for follow-up care after ovarian cancer.
Results from this study may help women with mutations who have had ovarian cancer consider their options, but decisions related to surgery or screening should still be based on your specific situation. Speak with your doctor or healthcare team about ways to reduce your breast cancer risk, such as regular screenings, preventive surgeries, or lifestyle changes.
Reference
Apostol AI, Gronwald J, Cybulski C et al. Risk of Breast Cancer After Ovarian Cancer in Women With a Pathogenic/Likely Pathogenic Variant in or . J Clin Oncology. 2026.
Disclosure: FORCE receives funding from industry sponsors, including companies that manufacture cancer drugs, tests and devices. All XRAYS articles are written independently of any sponsor and are reviewed by members of our Scientific Advisory Board prior to publication to ensure scientific integrity.
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posted 5/18/26
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