Published: 25 July 2024
A new study supported by NIHR has found that women treated for ovarian cancer caused by faulty BRCA genes have a lower risk of also developing breast cancer than previously thought.
Men and women who inherit faulty versions of the BRCA1 or BRCA2 genes have an increased risk of developing different types of cancers. These include:
- breast cancer
- ovarian cancer
- prostate cancer
- pancreatic cancer
Largest study to date
Researchers at the NIHR Manchester Biomedical Research Centre (BRC) looked at the risk of breast cancer in 701 women who had already been treated for ovarian cancer. The women all had faulty BRCA1 or BRCA2 genes. Their risk of breast cancer was assessed annually for each age group, and for up to 15 years following ovarian cancer diagnosis.
The results showed that for women with these genetic faults, the likelihood of developing breast cancer in the first five years after an ovarian cancer diagnosis was lower than for those without ovarian cancer. The researchers think this is because of the platinum-based chemotherapy that is often used to treat ovarian cancer.
Breast cancer rate for patients with faulty BRCA2 gene after ovarian cancer treatment
- 3.3% at 2 years
- 6.2% at 5 years
- 10.4% at 10 years
- 20.3% at 15 years
Breast cancer rate for patients with faulty BRCA2 gene after ovarian cancer treatment
- 2.1% at 2 years
- 5.0% at 5 years
- 15.0% at 10 years
- 29.1% at 15 years
Professor Gareth Evans, Consultant in Medical Genetics and Cancer Epidemiology at MFT and The University of Manchester and NIHR Manchester BRC Cancer Prevention and Early Detection Co-Theme Lead, said: “Many women we speak to who have a new diagnosis of ovarian cancer immediately ask about bilateral mastectomy (removal of both breasts) as an option to manage their cancer risk. Many are upset to hear they need to delay this to the required two-year point of disease-free survival from ovarian cancer.
“Our findings mean we can reassure women that their risk of breast cancer in the first two years after diagnosis is relatively low at around 2% to 2.5%. This is likely because of the effects of platinum-based chemotherapy, which is widely used to treat ovarian cancer, resulting in control and potentially complete eradication of breast cancers that otherwise could have occurred in the first five years.”
The results, published in Genetics in Medicine, show the low rate continues until 10 years of follow up. However the researchers cautioned that women need to be aware of the increased risk after 10 years.
Professor Evans said: “In women with good long-term life expectancy the higher risks of breast cancer after 10 years, particularly in BRCA1, should be discussed with their clinicians. This includes presenting all the available options such as MRI screening and risk
reducing mastectomy.”