prophylactic mastectomy in patients with BRCA mutations

Last reviewed 06/2022

A study enrolled 28 women with:

  • a family history of breast cancer
  • mutations in the BRCA genes which are known or suspected to cause breast cancer

The women are estimated to have had a 56-85% lifetime risk of developing breast cancer.

Women were given bilateral prophylactic mastectomies.

During the 15 year follow-up the researchers estimated that they would have expected to see 10.7 cases of breast cancer. In the trial none of the patients developed breast cancer.

This represents a relative risk reduction of 90% (95% confidence interval 50-100%) (1).

Risk-reducing mastectomy for women with no personal history of breast cancer (2)

  • bilateral risk-reducing mastectomy is appropriate only for a small proportion of women who are from high-risk families and should be managed by a multidisciplinary team
    • bilateral mastectomy should be raised as a risk-reducing strategy option with all women at high risk
    • women considering bilateral risk-reducing mastectomy should have genetic counselling in a specialist cancer genetic clinic before a decision is made
    • discuss the risks and benefits of risk reducing mastectomy with women with a known or suspected BRCA1, BRCA2, or TP53 mutation
      • offer women who have BRCA1, BRCA2 or TP53 mutations but who decide against risk-reducing mastectomy, surveillance according to their level of risk
    • pre-operative counselling about psychosocial and sexual consequences of bilateral risk-reducing mastectomy should be undertaken
    • the possibility of breast cancer being diagnosed histologically following a riskreducing mastectomy should be discussed pre-operatively
    • all women considering bilateral risk-reducing mastectomy should be able to discuss their breast reconstruction options (immediate and delayed) with a member of a surgical team with specialist oncoplastic or breast reconstructive skills
    • a surgical team with specialist oncoplastic/breast reconstructive skills should carry out risk-reducing mastectomy and/or reconstruction
    • women considering bilateral risk-reducing mastectomy should be offered access to support groups and/or women who have undergone the procedure

Breast cancer risk category

Near population risk Moderate risk High Risk *
Lifetime risk from age 20 Less than 17% Greater than 17% but less than 30% 30% or greater
Risk between ages 40 and 50 Less than 3% 3-8% Greater than 8%

*This group includes known BRCA1, BRCA2 and TP53 mutations and rare conditions that carry an increased risk of breast cancer such as Peutz-Jegher syndrome (STK11), Cowden (PTEN) and familial diffuse gastric cancer (E-Cadherin)

Reference: