Women with early-stage breast cancer who have a mutation in the BRCA gene are much less likely to die from the disease if they have a double mastectomy, compared with women who have the mutation and only have one breast removed. This is according to a study published in the BMJ.

The research team, including Prof. Steven Narod of the Women’s College Research Institute in Toronto, Canada, says the findings suggest that clinicians should discuss double mastectomies as a treatment option for young women with a BRCA mutation who are in the early stages of breast cancer.

BRCA genes – BRCA1 and BRCA2 – are human genes that produce tumor suppressor proteins that help repair damaged DNA and contribute to the stability of genetic material within a cell.

When these genes are mutated, this stops the production of tumor suppressor proteins and cells are more susceptible to genetic alterations that can lead to the development of cancer.

According to the National Cancer Institute, inherited mutations of the BRCA genes account for around 20-25% of hereditary breast cancers and 5-10% of all breast cancers.

Approximately 55-65% of women with a hereditary BRCA1 mutation and 45% with a hereditary BRAC2 mutation will develop breast cancer by the time they are 70 years old.

The researchers note that once women with BRCA mutations are diagnosed with breast cancer, their risk of second primary breast cancer significantly increases.

In North America, around 50% of women with a BRCA mutation will undergo a double mastectomy, but the investigators say that so far, there has been no evidence to suggest a double breast removal reduces the risk of death for these women.

In a attempt to find out, the research team analyzed 390 women from 290 different families who were diagnosed with early-stage breast cancer between 1977 and 2009. Women were followed-up for 20 years.

All women were either likely to be carriers of the BRCA1 or BRCA2 genes or known carriers.

Of the patients, 44 initially underwent a double (bilateral) mastectomy. A single (unilateral) mastectomy was initially performed on 346 of the women, and 137 of these had the other breast removed at a later date (contralateral mastectomy).

During the follow-up period, 79 women died of breast cancer. Of these, 18 had the double mastectomy and 61 had the unilateral mastectomy.

Results of the study revealed that a double mastectomy was linked to a 48% reduction in death as a result of breast cancer over a 20-year period, compared with a single mastectomy.

Furthermore, the investigators used the results to estimate that out of 100 women, 87 will be alive 20 years after a double mastectomy, compared with 66 women treated with a single mastectomy.

Commenting on the findings, Prof. Narod told Medical News Today:

We now recommend that all women with a BRCA1 or BRCA2 mutation and early stage breast cancer be treated with bilateral mastectomy. Also, genetic testing should be offered to more breast cancer patients at the time of diagnosis.”

However, the research team notes that further studies should be conducted in order to confirm these findings.

Prof. Narod told us that they plan to study the combination of bilateral mastectomy with other treatments, including oophorectomy (ovary removal surgery) and aromatase inhibitors.

Furthermore, the researchers want to determine the best treatment plan for patients that incorporates chemotherapy, surgery, oophorectomy and hormonal therapy.

“[We will also] explore the benefit of hormonal therapies in women with BRCA1 mutations and estrogen receptor-negative breast cancers,” Prof. Narod added.

In an editorial linked to the study, Dr. Karin Michels, of Harvard Medical School in Massachusetts, notes that although the findings of this research suggest a significant reduction in breast cancer deaths with a double mastectomy, whether to undergo the procedure is a difficult decision for women and this should not be overlooked.

“[Breasts] are essential parts of women’s identity, sexuality, and self perception. Parting with a breast may result in anxiety, lack of self esteem, and possibly depression. Parting with a healthy breast, or two, to prevent a probability is even more difficult,” says Dr. Michels.

“The decision to undergo a bilateral mastectomy is an individual and personal choice that a woman has to make together with her doctor.”

Medical News Today recently reported on a study suggesting that young female smokers who currently smoke and who have smoked for 10 years or more have a significantly higher risk for estrogen-receptor positive breast cancer.