New NICE guidance recommends that five years’ treatment with tamoxifen or raloxifene be made available as an option to women aged over 35 who are at moderate or high risk.
The decision could give as many as 500,000 women an alternative to mastectomy as a means of preventing breast cancer.
Tamoxifen, which has long been off-patent and is available in three generic branded forms, is likely to be cheaper than raloxifene (Lilly’s Evista).
Both drugs, if taken for five years, can reduce the risk of developing breast cancer by 40% for a decade.
However, they can have unpleasant side-effects. Tamoxifen can cause blood clots and hot flushes, and up to half of breast cancer patients prescribed the drug have given up taking it.
About 50,000 women are diagnosed with breast cancer in the UK each year, and one in five cases is thought to have a genetic cause.
Women in general have a one in eight chance of developing breast cancer, but women whose mother or sister has been diagnosed with breast cancer have a one in four chance (moderate risk), while women with the BRCA1 or BRAC2 gene have a 90% chance (high risk).
Breast nurse specialist and NICE advisor Susan Heard said: “Tamoxifen is not an expensive drug – to give a woman five years of tamoxifen would only cost about £130 – it can cost £12,000 to treat a woman for breast cancer in a year.”