In a small but long-term study in the US and Canada, researchers found that women who had both breasts removed after their first cancer had a 48 percent higher chance of surviving after 20 years than those who had just one removed.
But experts said that the procedure, though beneficial, could have a huge emotional impact and agreed that it should never be entered into lightly.
Women who carry a BRCA1 or BRCA2 gene mutation have a 60 to 70 percent chance of getting breast cancer in their lifetime, and also face a high risk of developing a second breast cancer even if one breast is removed.
Although less than three per cent of all breast cancers are caused by these genes, the grim outlook associated with them makes them a major area of research.
Angelina Jolie has the defective gene BRCA1, and her announcement that she had undergone a double mastectomy to cut her risk to around 5 percent significantly raised awareness of the procedure, and of the genetic basis of some breast cancers.
The study is published in the British Medical Journal (BMJ).