Breast cancer drug will boost survival rates

A breast cancer treatment is being launched this week that specialists describe as the most important advance in drug therapy for 25 years.

The drug, Arimidex, has been approved for use in early breast cancer after surgery and offers an alternative to the hormonal treatment tamoxifen, which has been the gold standard since the 1970s and has helped to cut breast cancer deaths by 25 per cent over the past decade.

The biggest study of a cancer therapy showed earlier this year that Arimidex, whose chemical name is anastrozole, caused fewer-side effects than tamoxifen and reduced the risk of the cancer recurring. The results of the study of 9,300 patients were announced in America in May.

Jeffrey Tobias, professor of cancer medicine at University College Hospital, London, and joint leader of the study, said yesterday: "Tamoxifen is the world's most widely prescribed cancer drug and it has stood the test of time. It is very rare for a drug that has worked so clearly and so effectively to be challenged by one that is both more effective and less toxic."

Dr Michael Dixon, consultant surgeon at the Edinburgh breast unit, Western General Hospital, said: "The evidence to show Arimidex may further improve on the benefits already seen with tamoxifen is very exciting."

After three years of trials Arimidex, which is produced by AstraZeneca, is already showing a small survival benefit for women with early breast cancer but doctors believe that in the long term it could extend the lives of thousands of women.

It has been licensed for use in advanced breast cancer since 1995 but is to be extended for use by the estimated 18,000 womenwith early stage post-menopausal, oestrogen receptor positive disease. Some 33,000 women are diagnosed with breast cancer in Britain each year.

The licensing authorities are initially restricting use of Arimidex to women who have a high risk of blood clots or endometrial cancer (for the lining of the womb) which could be increased by tamoxifen. Mary Morrissey, 43, wasprescribed Arimidex for a blood clot in her lung. She had been diagnosed with aggressive breast cancer in November 1999, and while undergoing chemotherapy and radiotherapy after a mastectomy she suffered the pulmonary embolism. Her cancer specialist prescribed Arimidex as an alternative to tamoxifen.

Ms Morrissey said: "Many of the ladies in my breast cancer support group were on tamoxifen and I knew very little about Arimidex. But my doctor said it was a superior drug."

After two years on the drug, she says she has had few ill- effects. She walks 30 miles a week and has lost 24 kilograms since the end of her treatment.

"I had a few hot flushes at first but with time they subsided. I didn't get weight gain like some women. My energy levels are up and I feel well."

Research shows Arimidex reduces the risk of cancer occurring in the other breast by 75 per cent, compared with 50 per cent on tamoxifen, and cuts the risk of endometrial cancer from one in 200 to one in 1,000. It halves the rate of vaginal bleeding and cuts the incidence of blood clots by 70 per cent. It does, though, increase the risk of joint pains and fractures

It is also ten times more expensive than tamoxifen at about £1,000 a year or £5,000 for the standard five-year course. Doctors say that this is less than the cost of many other less-effective treatments. Ms Morrissey said: "I don't think cost should be a factor."

Specialists say there is no evidence that women taking tamoxifen would benefit from switching to the new drug. Professor Tobias said: "I am absolutely against patients on tamoxifen switching. I strongly feel they are taking an excellent drug which the majority are tolerating extremely well. There is no need to switch."