Breastfeeding can reduce a BRCA1 carrier's lifetime risk of breast cancer by about 32%. However, the starting line is so high, up to 60%, that even a diligent nursing history cannot reduce the risk to the average. Current guidelines call for annual MRI from age 25-<40, with mammograms added at 40, because missing a tumour in these women can cost decades of life.
Key Facts at a Glance
Understanding your risk of cancer can be complicated. It becomes even more complex when multiple factors are impacting breast cancer risk at the same time. Key statistics to be aware of include:
- Baseline risk: BRCA1 ≈ 60% and BRCA2 ≈ 45% lifetime risk1.
- Risk reduction with breastfeeding: 32% for BRCA1; no proven drop for BRCA22.
- Baseline risk for all women: 1 in 7, about 14%3.
- MRI advantage: MRI plus mammogram detects 9-100% of cancers in high-risk young women vs ≈ 25-59% for mammograms alone4.
- Start line: Annual MRI starting at age 25 for BRCA1/2 carriers5.
Screening recommendations can vary depending on the presence of other risk factors such as mutations other than BRCA1 and previous radiotherapy on breast tissue5.
Why Breastfeeding Helps but Doesn’t Erase High Risk
It may come as a surprise to learn that breastfeeding can reduce the risk of breast cancer for BRCA1 carriers. There are several potential mechanisms behind this connection.
Imaging Timetable for High-risk Postpartum Women
Breast cancer screening programmes are customised based on individual risk factors. In the UK, MRI is not recommended during pregnancy or lactation, as changes to breast tissue during these times can impact image quality and reduce the benefits of MRI. Screening can resume three months after giving birth and after the cessation of breastfeeding for women who opt out of screening due to pregnancy or lactation5,10.
Beyond Imaging: Complementary Risk Reducers
There is a wide array of factors that can contribute to higher breast cancer risk. Fortunately, there are several behavioural changes and treatment options that can help to reduce it. These include:
- Weight vigilance - Maintaining a healthy weight is important, as a body mass index (BMI) of 30 or above is associated with a 70% higher risk of post-menopausal breast cancer11.
- Alcohol cap - Limiting alcohol intake is advised, since each additional daily drink (10 grams of alcohol) increases the relative risk of breast cancer by approximately 7%12. Limiting alcohol consumption to less than 14 units a week may help to lower the risk13.
- Chemoprevention - Medications such as tamoxifen and raloxifene may reduce breast cancer risk for individuals with BRCA1/2 mutations14.
- Prophylactic surgery - Risk-reducing bilateral mastectomy can lower the likelihood of developing breast cancer by over 90% for people at high risk, such as those with BRCA mutations15. However, the decision and timing of surgery are highly personal and depend on individual circumstances.
Barriers to Screening Services for Breast Cancer
Despite improvements in our understanding of breast cancer risk, significant barriers remain that prevent women from benefiting from MRI screening. It is estimated that about 73 preventable breast cancer deaths occur in the UK each year due to unequal access to screening infrastructure16.
Besides accessibility issues, women may avoid attending breast screening appointments due to not thinking they are at risk, fear of pain during the screening, fear of a cancer diagnosis, lack of time, and poor accessibility, among others17.
Mobile screening units offer a potential solution by bringing screening services closer to women with limited mobility or living in more remote areas. Improved engagement of healthcare bodies with faith-based groups or social networks can help to improve awareness of breast screening programmes among historically underserved communities17.
Talk to Your Healthcare Provider
Every individual has a unique set of risk factors relating to breast cancer. An important first step is understanding your risk, which can involve attending a genetic counselling service. If close relatives of yours have had ovarian or breast cancer, you may be entitled to an NHS genetic test, which can identify high-risk mutations such as those in BRCA genes18.
If you are in a high-risk category and are pregnant or have recently given birth and are breastfeeding, it’s important to discuss your screening options with your doctor. They will be able to advise you on the pros and cons of continuing screening as usual or waiting until after pregnancy and breastfeeding19.
Summary: Breastfeeding, BRCA, and Beyond
Breastfeeding can lower the risk of breast cancer in individuals with BRCA1 mutations, but on its own, it does not eliminate the elevated risk. Early, MRI-based surveillance remains a crucial tool for early cancer detection, as does overcoming barriers to accessing screening infrastructure. Getting informed about your risk and discussing your screening options with your healthcare provider can help you to make informed decisions about your health, through pregnancy, breastfeeding, and beyond.
If you want to be proactive about your breast health, consider booking an Ezra MRI scan. Our service helps to detect abnormalities early, giving you the best chance of early treatment and improved outcomes.
