It is a distressing fact that one in 12 women in the UK will develop breast cancer.

The discovery of a breast lump can shake women to their very core, leaving them fearing for their lives and the welfare of their children.

The dread of developing the disease is compounded if a woman has watched a close relative suffer from breast cancer. The assumption is if it happened to someone in their family it will happen to them.

Some women give up smoking, start exercising and watch their diet to try to improve their chances of remaining cancer free. Others look into a much more radical preventative step: a bi-lateral mastectomy, having both breasts surgically removed.

Once a woman realises a strong family history could mean she is at risk and accepts she could live without her breasts if it offered protection, a highly involved process of testing, counselling and medical investigations is opened up.

But the number of women who actually reach the stage of surgery is very small. Michele Stacey, manager of the Nigel Porter Unit, the breast care clinic at the Royal Sussex County Hospital, in Brighton, said the hospital only performs one or two preventative bi-lateral mastectomies each year.

The latest case came earlier this month when Chantal Heaven, from Bristol, attended the Brighton unit for a consultation before having her breasts removed.

Michele said: "If it comes to considerations of surgery a woman has to look at how she is going to feel, how she is going to look, how she is going to form a relationship, how her children are going to cope if they are cuddled and breasts are not there.

"A lot of women just want to come in and talk about the risks rather than specifically being interested in surgery. With many it's more to do with having seen other family members with breast cancer. It's the fear of getting the disease.

Last November Sussex television presenter Sally Taylor touched viewers with a documentary about her double mastectomy. She opted for the procedure after discovering cancerous cells were present in her right breast. She had also lost her mother to breast cancer.

She said: "I weighed up the odds and then asked for a double mastectomy because if there was any chance of a further spread of cancer I'd rather deal with it and not worry."

Although it was a high-profile case less than five per cent of breast and ovarian cancers can be traced back to a genetic mutation passed on through the generations.

But if women learn they are carrying a defective gene they carry that information with them for the rest of their lives. It can affect their jobs, insurance and emotional health. As a result health specialists are careful before steering women along the course of finding out.

Establishing whether the defective gene is present involves a complex process of tracing which female relatives have had cancer, over how many generations, how old they were and how closely related.

Dr Penny Bridger, a consultant in public health medicine with East Sussex, Brighton and Hove Health Authority, said: "Many women probably think there is some sort of magic test that can be done to find out whether they are going to develop cancer. It's more complicated than that. It's not as simple as just having cancer in your family."

In the rare cases where a genetic mutation is detected women are talked through preventative steps, like regular mammograms. The option of preventative surgery might also be raised.

But Dr Bridger explained a preventative mastectomy is not a cast iron guarantee against developing the disease because traces of breast tissue might be left behind. She said: "For a woman to take the step of having a bi-lateral mastectomy I would like to think she has seen all the appropriate people before undergoing radical surgery which is not a 100 per cent guarantee. Breast cancer treatment has also improved during the past ten years."

Sue Warren, from Brighton, was diagnosed with cancer three years ago and had her left breast removed. She had a strong history of cancer in her family and has talked to her two daughters about the possibility of gene testing. Both have chosen not to have it done.

Sue, 54, explained: "Their feeling was one of wondering what they would do with the information if they found out. They would be carrying that information around with them forever. My advice to women having mastectomies would be to have a reconstruction at the same time. I waited one year for mine and waking up and seeing I had cleavage again was a wonderful feeling."