The risk of women carrying a BRCA1 or BRCA2 mutation developing breast cancer before they are 80 years old is about 70% compared with 12% in women without the mutation.

What is the risk of breast cancer associated with BRCA mutations?

Women in the UK have a 1 in 8 chance (12.5%) of developing breast cancer during their lifetime.  Over 80% of all breast cancers occur in women over 50 year of age.

 

Women who have one or two close relatives with breast cancer have a higher risk of breast cancer, ranging from 17% to 30%

For women with a BRCA1 or BRCA2 mutation the breast cancer risk to age 80 years is 72% for BRCA1and 69% for BRCA2 carriers. Breast cancer risk begins to rise in the late twenties and thirties for BRCA1 and in 40s and 50s in BRCA2 and remains high for the rest of their lifetime.

For a woman who has already had one breast cancer the risk of developing another new breast cancer in the other breast within the next 20 years is 40% for BRCA1 and 26% for BRCA2 compared with 10% for women without BRCA mutations.

There are different types of breast cancer and in women with BRCA1 mutations, 70% of tumours are triple negative (oestrogen, progesterone and HER2 receptor negative), whereas 70% of tumours with BRCA2 mutations are oestrogen receptor positive.

 

Breast cancer in BRCA carriers

For women diagnosed with breast cancer who are known to carry a BRCA 1 or BRCA2 mutation, it is important to discuss how this may change the treatment options.  Women with BRCA mutations have a higher risk of developing another cancer in the same breast or in the other breast and may want to consider surgery to remove both breasts either at time of diagnosis or at some stage in the future.

It is important to remember that the priority is to treat the current cancer and that surgery to prevent further cancers will not improve the survival outcome in the next 5 years.

There are targeted chemotherapy treatments which offer improved survival for women with BRCA mutations and there may be clinical trials of newer drugs open for women with BRCA mutations.  When considering the treatment options of oestrogen receptor positive breast cancer in pre-MENOPAUSEal women with BRCA mutations it may be recommended to have the ovaries removed in combination with drugs suitable for post-MENOPAUSEal women.

How can I manage my risk of breast cancer?

Women living in the U.K. who are shown to carry a BRCA mutation will be offered annual breast screening from age 30.

Risk-reducing surgery with removal of the breast tissue from both breasts before a diagnosis of breast cancer will reduce the risk of breast cancer by about 95% Chemoprevention uses drugs that can reduce the risk of breast cancer but these may have less benefit for women with BRCA1 mutations.

Lifestyle factors including taking regular exercise, not being overweight, eating a healthy diet and not drinking too much alcohol have been shown to reduce the risk of post-menopausal breast cancer in the general population by 30%.

Further research is required to consider the impact of lifestyle factors in BRCA carriers however some studies have shown that a healthy lifestyle as a teenager and young adult may delay the onset

of cancer in women with BRCA mutations.

A healthy lifestyle, particularly exercise will help improve the outcomes for women who have been diagnosed with breast cancer and can reduce the complications associated with major breast

surgery.