The NHS is considering providing preventative medication to women with a family background of breast cancer.
A draft consultation has been launched by the National Institute of Health and Clinical Excellence (NICE) to decide whether the drugs tamoxifen or raloxifene should be given to high-risk post-menopausal females in England and Wales, namely those with a family history of cancer. The disease claims the lives of 12,000 Britons a year.
Taking tamoxifen over a five-year period lessened the chances of getting invasive breast cancer by around 50 per cent in high-risk post-menopausal women, an earlier clinical trial discovered. The risk was reduced by 38 per cent in a similar trial for raloxifene.
Under the NICE guidelines, some women could be offered their first mammogram at a younger age. Women aged 40 and over considered to be at high or moderate risk of developing cancer would be invited for breast screening, which is currently only available to women between the age of 50 and 70.
Genetic screening could also be introduced by the NHS to discover whether people with a family history of the disease have faulty genes which may increase the likelihood of breast cancer.
Breakthrough Breast Cancer chief executive Chris Askew described the consultation as a "historic step" for the prevention of the disease. It is the first time drugs have been recommended as a way of reducing the risk of breast cancer in Britain.
Mr Askew added: "This is exciting as, even though most women do not have a significant family history of the disease, it's crucial that those who do have an array of options to help them control their risk."
He added that the new guidelines would offer fresh challenges to the NHS, with a marked increase in genetic testing likely.
Professor Mark Baker, director of the Centre for Clinical Practice at NICE, said: "It's wise for any person with a family history of cancer to receive appropriate investigations and screening that would otherwise be unnecessary if a family history did not exist."
In the region of 50,000 women and 400 men are diagnosed with breast cancer each year, making it the most common cancer in Britain.