UK breast cancer rates are rising

The Boadicea program is more accurate than alternatives because it takes into account a greater number of genetic mutations linked to cancer.

The researchers, from Cancer Research UK, plan to offer it to health professionals to help them identify women who need further tests.

Details of the program are published in the British Journal of Cancer.

Women with a strong risk of breast and ovarian cancer can be offered pre-emptive measures such as screening from an early age, preventative surgery (removing breasts or ovaries) or drugs such as tamoxifen.

BREAST CANCER WARNING SIGNS Changes in the shape, appearance or feel of the breasts A lump in one breast or armpit which is different from the other side or is new Any puckering or dimpling of the skin Nipple discharge, a rash or a change in nipple position Pain or discomfort in one breast that is different from normal

But the genetic tests needed to identify women as having genetic mutations in genes such as BRCA1 and BRCA2 are expensive.

They can also be slow, causing considerable anxiety in the many patients who turn out not to be at high risk.

Professor Doug Easton, of the Cancer Research UK Genetic Epidemiology Unit in Cambridge, said: "We created the Boadicea program in order to better target genetic testing towards only those women who are most likely to carry the mutations.

"Boadicea works out a woman's breast and ovarian cancer risk using detailed information on her family history of cancer.

"The program calculates both her risk of carrying a particular cancer-causing mutation, and her overall risk of developing breast or ovarian cancer."

Good results

The program predicts cancer risk based on detailed genetic data gathered on 1,484 women with breast cancer and 156 families with multiple breast and ovarian cancer cases.

BRAC GENES Women who inherit a damaged BRCA1 gene have a 60-85% chance of developing breast cancer They also have a 20-40% chance of developing ovarian cancer For BRCA2, the risks are 40-60% and 10-20% respectively Around 1 in 1,000 women in the UK carry a damaged version of the BRCA1 gene and 1 in 700 carry a faulty BRCA2 gene

The team has just finished testing the program's accuracy by using it to predict high genetic risk of breast cancer in women whose family histories were collected in the past by doctors.

Comparing Boadicea's answers to the results of genetic tests in those women has confirmed the program's strength.

Many genes are responsible for a woman's inherited risk of breast cancer. Most of these genes have only a small effect on their own, but working together they are a strong influence.

The detailed family data the team has used to put Boadicea together means the program can take the influence of all of these genes into account - even those genes for which there is no biological test.

Professor Easton said: "BRCA1 and BRCA2 together account for under 20% of breast cancer clusters in families, so for a computer program of this nature to be accurate it is vital it can take other mutations into account.

"Having put the finished product through its paces by rigorously testing it, we have confirmed that it is more accurate than any such program created in the past."

The team is currently making Boadicea more "user friendly" and plans to make it available via the web to oncologists and geneticists.

The next step will be to increase the program's power by making it possible to input information on women's non-genetic risk factors, such as breast-feeding, age at menopause and the number of children she has had.