A third of UK women would consider having both breasts removed to reduce the risk of cancer, a survey suggests.
Most breast cancers are not hereditary
While most are not at high risk, a small minority with a strong genetic predisposition have an 80% chance of developing breast cancer in their life.
For these women a choice other than double mastectomy or watchful waiting is desperately needed, says Cancer Research UK which surveyed 1,500 women.
It is conducting a major trial to test a drug that might prevent the cancer.
A sample of 1,500 women were asked what they would do if they found out they were at very high risk of developing breast cancer.
Half said they would be willing to take a daily tablet to reduce their cancer risk and the same number said they would volunteer to test a candidate drug.
Emma Pennery, nurse consultant at Breast Cancer Care who provides information and support to women making these decisions, said: "I'm not surprised by the figures found.
"Very often women who are deemed to be at very high risk do have genuine cause for concern.
"It's a very frightening time and a sort of time bomb way of living. The worry can really dominate these women's lives.
"To be able to do something to reduce that risk is very attractive to a lot of women even though it is radical. It is very difficult to decide to have healthy tissue removed though.
"The key thing is to make sure their reasons for doing it are valid."
She said many women misinterpret their risk and believe it was much higher than it is.
Reconstructive surgery can be an option after mastectomy
She said the majority of women who opt for double mastectomy do not regret their decision.
Others choose instead to have regular surveillance and screening.
"Anecdotally, many women say they would be very optimistic about taking a tablet to prevent cancer. It's not permanent like surgery and is something that can be stopped."
Currently there is no one drug that prevents breast cancer but the charity is testing one candidate, anastrozole.
Cancer Research UK is rolling out its trial into anastrozole as a preventive therapy to recruit from around the world 10,000 healthy women who are at an increased risk of the disease.
It is already used to treat women who have breast cancer that is hormone sensitive, meaning it grows when exposed to the female hormone oestrogen. Most breast cancers are hormone-sensitive.
Anastrozole used in this way can reduce the risk of cancer developing in the opposite breast by over 50%, trials have shown.
Cancer Research UK hopes to find out whether it can also prevent cancer in the first place.
Professor Jack Cuzick, lead researcher on the trial, said: "We are very optimistic based on data using this drug for the treatment of breast cancer. "
He said that by using it for prevention, "we might potentially get rid of about 75% of hormone-responsive breast cancer".
It also has the advantage of fewer side effects than the other drug candidate, tamoxifen, they had considered initially, he said.
Information about the trial can be found at the IBIS website. The survey was conducted by research agency NOP World.
Dr Sarah Rawlings from Breakthrough Breast Cancer said: "Increasing the preventative options available, such as being able to take anastrozole, would be extremely welcome and we hope that women will join this trial."