Preventative Mastectomy: Odds Might Pay Off

Preventative mastectomy increased odds of 20 year survival in women with breast cancer

(RxWiki News) When faced with breast cancer in one breast, some women carrying the breast cancer gene have elected to have the other breast removed, too. Does this decision increase their odds of survival?

A research team from Canada recently published a study investigating the 20-year survival of BRCA-positive women undergoing double mastectomy (surgical removal of both breasts).

The results of this study showed that more women with BRCA gene mutations and breast cancer would be alive in 20 years if they chose to have the other breast surgically removed, in addition to the breast with cancer.

"Follow your doctor's directions for having mammograms."

This research was conducted by a study team that included Kelly Metcalfe, PhD, from the University of Toronto in Canada.

Women with mutations in the BRCA genes have a high risk of developing breast cancer. After developing cancer in one breast, some women with these high-risk gene mutations opt to have both of their breasts surgically removed. Preventing a second breast cancer is the aim of having their non-cancerous breast removed.

This study enrolled women with a BRCA1 or BRCA2 mutation diagnosed with stage I or II breast cancer between 1977 and 2009. The study included 390 women who had a single or double mastectomy after diagnosis of cancer in one breast.

The average age of the women was 41 to 44 years, and the women were followed for up to 20 years, with an average follow-up of 13 years. Previous studies on this topic only looked at 10-year survival.

The researchers collected additional data on the women, including tumor information, use of chemotherapy and whether the second breast was removed as a future cancer prevention strategy.

During this study, 61 of the 209 single mastectomy patients and 18 of the 181 double mastectomy patients died from breast cancer.

Analysis of the data showed that women who had a double mastectomy had a 42 percent decrease in the odds of dying during the study period compared to women who had a single mastectomy. This increased survival benefit was greatest in years 10 to 20 after the first breast cancer diagnosis.

Average 20-year survival rates were 88 percent for women who had a double mastectomy and 66 percent among single mastectomy patients.

Dr. Metcalfe and her team summed up their work by stating, “We conclude that it is reasonable to propose bilateral mastectomy as the initial treatment option for women with early stage breast cancer who are carriers of BRCA1 or BRCA2 mutation.”

The choice to remove a breast without cancer is still considered a controversial option and is a highly personal decision for women.

The authors of this study noted some limitations of their work. One limitation was that the researchers assumed that 54 women in the study had the BRCA mutation, but this was not confirmed by genetic testing.

This research by Dr. Metcalfe and colleagues was published in the February issue of BMJ.

The researchers declared no conflicts of interest.

The Canadian Breast Cancer Foundation provided funding for this study.

Review Date: 
February 17, 2014