Many women who are considered to be at high risk for developing breast or ovarian cancer are choosing to undergo preventive mastectomy (removal of breasts) and/or oophorectomy (removal of ovaries) in order to reduce their risk of developing the disease, according to a study published in Cancer Epidemiology, Biomarkers, & Prevention.

Inherited mutations in two genes—BRCA1 and BRCA2—have been found to greatly increase the lifetime risk of developing breast and ovarian cancer. Mutations in these genes can be passed down through either the mother’s or the father’s side of the family. Women with a BRCA mutation have a 36-85% lifetime risk of developing breast cancer and a 16-60% lifetime risk of developing ovarian cancer; these statistics are compared with a 13% lifetime risk of breast cancer and a 2% lifetime risk of ovarian cancer in the general population.

In order to reduce the risk of developing either cancer, some women will opt for removal of the breasts and/or ovaries. Researchers in the UK investigated the rate of women who undergo this procedure and the impact of risk, timing, and age on the choice to have surgery. The study involved 211 known unaffected BRCA1/2 mutation carriers as well as 3,515 women at a greater than 25% lifetime risk but without mutations.

The results indicated that 40% of the 211 mutation carriers underwent bilateral risk-reducing mastectomy (BRRM) and 45% underwent bilateral risk-reducing sapingo-oophorectomy (BRRSO). The BRRSO was more common among BRCA1 mutation carriers, with 52% of these women choosing the surgery compared with 28% of women with a BRCA2 mutation.

Of the women with an increased lifetime risk but no mutation, fewer opted for preventive surgery:

  • Of women with a 40-45% lifetime risk, 6.4% underwent BRRM.
  • Of women with a 33-39% lifetime risk, 2.5% underwent BRRM.
  • Of women with a 25-32% lifetime risk, 1.8% underwent BRRM.

In evaluating the factors associated with the choice to undergo preventive surgery, the researchers found that age and level of risk impacted the decision:

  • Older women were less likely to undergo mastectomy but more likely to undergo oophorectomy.
  • Women with a higher risk factor were more likely to undergo surgery.
  • Women who underwent biopsy after risk evaluation were twice as likely to undergo BRRM.
  • Women typically opted for surgery within two years after the genetic mutation test; however, some waited up to seven years.

The researchers that concluded careful risk counseling influences a woman’s decision to undergo preventive surgery. They particularly suggest long-term follow-up in women who choose to delay BRRSO.

Reference: Evans GR, Lalloo F, Ashcroft L, et al. Uptake of risk-reducing surgery in unaffected women at high risk of breast and ovarian cancer is risk, age, and time dependent. Cancer Epidemiology, Biomarkers & Prevention. 2009; 18:2318-2324.

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