Bone drug cuts breast cancer risk

A DRUG given to middle-aged women to protect their bones has been found to cut the risk of breast cancer by more than three-quarters.

The results of the three-year study are even more dramatic than preliminary trials of the drug, Evista, which showed a halving of breast cancer. If the size of the effect is confirmed by further research, it could lead to the drug becoming a standard treatment offered to all women after menopause.

The new findings are based on a trial of 7,700 women in 25 countries and are published in the Journal of the American Medical Association. Among the 5,000 women given Evista, whose chemical name is raloxifene, there were 13 cases of breast cancer compared with 27 cases among the 2,500 women given a placebo - a 76 per cent reduction in risk.

Evista, made by Eli Lilley, was launched in the UK last September and has initially been licensed as a treatment for the bone thinning disease osteoporosis. In addition to its potential as a preventive treatment against breast cancer, it also reduces cholesterol levels and the risk of heart disease.

Evista is the first of the selective oestrogen receptor modulators (SERMs), refined versions of HRT that have an oestrogen-like effect in some tissues but block it in others. It is a cousin of tamoxifen, the breast cancer treatment, and appears to combine the benefits of tamoxifen and HRT without their disadvantages - increased risk of endometrial cancer (of the lining of the womb) in the case of tamoxifen and slightly increased risk of breast cancer with long-term use of HRT.

Dr Steven Cummings and colleagues at the University of California say in the journal that Evista has positive oestrogenic effects on bone, increasing bone density, and on blood, but does not have oestrogenic effects on breast and endometrial tissue.

But the drug led to a threefold increase in the risk of venous thrombosis (blood clots in the legs). The authors warn that women with a history of blood clots should not take Evista. They add that, on the basis of their results, to prevent one case of breast cancer, 126 women would need to be treated with the drug. In the UK, it costs pounds 20 for a month's supply.

In an accompanying editorial, Dr Adele Franks from the Prudential Centre for Healthcare Research in Atlanta says the findings provide "solid encouragement" in the search for the "perfect SERM that will duplicate or improve on the beneficial effects of oestrogen while protecting against its risks".

She adds: "Raloxifene should not be considered suitable by most women at this time but its contributions to knowledge intensify the anticipation of finding something even better on this new frontier."