Women with a gene which greatly increases their risk of developing breast cancer have a much higher chance of survival if they have a double mastectomy, new research suggests.
A study published online in the British Medical Journal found that over 20 more lives could be saved per 100 women treated if they opted to have both breasts removed rather than just one.
Campaigners said the findings could bring hope to thousands of women having to make important decisions about what is best for their health.
The researchers, from the United States and Canada, looked at women with faulty BRCA1 and BRCA2 genes – which cause a high risk of hereditary breast cancer – who had also been diagnosed with the earliest stages of the disease.
Hollywood star Angelina Jolie underwent a double mastectomy last year as a preventative measure to cut her risk of developing breast cancer in the future after discovering she carried the genetic mutation.
Current NHS guidelines state that double mastectomies are just one option for women with the BRCA gene mutations, with some opting to have just one breast removed if they have already been diagnosed with cancer and others opting for increased screening.
Women with faulty BRCA genes have a 45 per cent to 90 per cent lifetime risk of developing breast cancer and also have a higher risk of ovarian cancer.
In the latest study the researchers, led by Steven Narod at the Women’s College Research Institute in Toronto, looked at 390 women from 290 different families with early stage breast cancer, diagnosed between 1975 and 2009. The women were either known carriers of faulty BRCA1 or BRCA2 genes, or likely to be carriers, and had either a single or double mastectomy.
Some 44 women had a double mastectomy, while 346 had a single mastectomy. Of those who had a single mastectomy, 137 went on to have the other breast removed at a later date.Over a 20-year follow-up period, 79 women died of breast cancer. This included 18 of those who had a double mastectomy and 61 who had one breast removed.
The results showed that having both breasts removed was linked to a 48 per cent reduction in the risk of dying from breast cancer compared with having just one breast removed.
The researchers predicted that, of 100 women treated with a double mastectomy, 87 would be alive after 20 years compared to 66 of 100 in the other group. They concluded it was “reasonable to propose bilateral mastectomy as the initial treatment option for a woman with early stage breast cancer who carries a BRCA1 or BRCA2 mutation.”
The researchers said a double mastectomy should be discussed as an option for young women with a BRCA mutation and early onset breast cancer.
However, they called for further studies given the small number of women in this group. James Jopling, director for Breakthrough Breast Cancer in Scotland, said: “The question of whether or not to have a double mastectomy is a daunting one for any woman to face, especially given how worrying a time a breast cancer diagnosis can be.
“Anything that could help women feel fully informed of the risks and benefits when making such a personal decision is welcomed but we are very aware that this is a small study. At the moment, we know a double mastectomy can help reduce the risk of women developing a second breast cancer, but if more research can also show the procedure improves overall survival, this could provide much needed reassurance for women.
“When you take into consideration that many of these women who carry a faulty BRCA gene may have seen their families devastated by breast cancer for many generations, this could bring new hope to thousands.”