Women taking a new breast cancer drug are living longer than those taking Tamoxifen - the current 'gold standard' treatment.
Doctors predict the new drug, Arimidex, will improve long-term survival for women using hormonal therapy for the first time in decades.Tamoxifen
Claimed as the biggest breakthrough in treatment for 20 years, it is the first drug to challenge tamoxifen, the standard treatment for postmenopausal women after surgery.
Trial results out yesterday show the risk of a relapse within four years of surgery is cut by almost a fifth more in women taking Arimidex.
Only 413 of 3,125 women taking the new drug had a breast cancer relapse or died compared with 472 of 3,116 women using tamoxifen.
The latest research findings show Arimidex is much more effective than tamoxifen, which is normally used to stop patients successfully treated with surgery from developing a tumour in the other breast.
Previous trial results found that although tamoxifen halves the risk of a new cancer in the other breast - Arimidex halves it again.
Women taking Arimidex also suffer fewer cases of deep vein thrombosis and womb cancer - known sideeffects of tamoxifen use.
Professor Jeffrey Tobias, Professor of Cancer Medicine at University College and Middlesex School of Medicine and one of the trial investigators, said: 'The results show that women taking Arimidex remain disease-free for longer than those on tamoxifen - so far we have observed fewer recurrences and a longer time before relapse in these patients.'
The study of 9,300 post-menopausal women worldwide, including 3,000 Britons, involves women being given Arimidex, tamoxifen or both.
It shows that women with tumours that respond to hormonal therapy have an 18 per cent lower risk of a relapse after about four years of treatment, according to results released at the San Antonio Breast Cancer Symposium, Texas.