Prophylactic mastectomy in patients with BRCA mutations

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

*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:

• Hartmann, L. American Association of Cancer Research meeting April 2, 2000.
• NICE (June 2013). Familial breast cancer - Classification and care of people at risk of familial breast cancer and management of breast cancer and related risks in people with a family history of breast cancer