Breast cancer drug breakthrough

A new breast cancer drug is so effective it will see the end of the current "gold standard" treatment Tamoxifen, researchers said today.

The new drug, anastrozole, performed much better in a five-year trial, but it costs 40 times more than Tamoxifen, taken by hundreds of thousands of women in Britain.

If they all switch to the new treatment, it will cost the NHS £100 million a year.

Anastrozole, sold as Arimidex, is one of a new class of drugs called aromatose inhibitors, shown to be highly effective at preventing the disease recurring, reducing the spread of a cancer and stopping it appearing in the other breast.

In all these areas it has outperformed Tamoxifen, which has been the best drug available for 20 years and which is being taken by 100,000 British women at any one time.

A year's treatment costs between £25 and £30 per patient. Anastrozole would cost £1,000.

Half of all suitable patients - post-menopausal women with hormone-sensitive breast cancer - are taking anastrozole in the US, but it may not be licensed for use here for several years. It can, however, be prescribed privately.

The research was being presented today at the San Antonio Breast Cancer Symposium by Anthony Howell, research director and breast cancer expert at Christie Hospital NHS Trust, Manchester.

He said: "It is the beginning of the end for Tamoxifen. It's clear this drug is going to take over.

"Tamoxifen should be replaced for two reasons: anastrozole is much more effective and there are many fewer side effects."

In the trial comparing anastrozole with Tamoxifen, the former increased disease-free survival by more than 10 per cent, increased the time to disease recurring by about 20 per cent, reduced cancer spreading by 14 per cent, and reduced cancer occurring on the other breast by more than 40 per cent.

Aromatose inhibitors such as anastrozole appear to be effective because they prevent the body producing oestrogen, which "feeds" the cancer, whereas Tamoxifen simply combats the effects of oestrogen in cancer cells.

Dr Sarah Rawlings, policy manager at the charity, Breakthrough Breast Cancer, said: "This is welcome-news for postmenopausal women with early stage breast cancer of this type which is hormone sensitive.

"Options like Arimidex could make a real difference-However, it is not fully licensed in the UK and women should not be discouraged from continuing with Tamoxifen as it is the best option currently available."