Test to aid women with breast cancer

Women with breast cancer will soon be able to take a test that predicts whether the drug tamoxifen could help them fight the disease.

About 30 per cent of breast cancers that are treated with tamoxifen do not respond to the therapy, and a team at Cancer Research UK has now discovered a "key chemical switch" that makes tumours resistant to the drug.

Sir Paul Nurse, interim chief executive of Cancer Research UK, said: "Tamoxifen is effective for many breast cancer patients, but it does not work for everyone. By identifying those women who won't respond to the drug, doctors can explore other avenues of treatment more rapidly."

Breast cancer is one of the fastest rising cancers, with about 3,000 new cases in the UK each year. Tamoxifen improves the chances of survival of women with "oestrogen-receptor positive" breast cancers – that is, those whose growth is encouraged by the female hormone oestrogen – by binding to the oestrogen receptors, in effect stopping signals to the tumour to grow.About 50 per cent of breast cancers are oestrogen-receptive, and about 70 per cent of these type of cancers – or about 35 per cent overall – are treated successfully with tamoxifen.

Dr Simak Ali, of Imperial College London, a lead author of the study, said: "It's important that we learn to identify women who are not going to respond to the drug, so we can spare them from unsuccessful treatment and explore other ways of looking after them."