Drug switch improves breast cancer survival

By Patricia Reaney

LONDON (Reuters Life!) - Switching patients with early breast cancer from a standard drug to a newer treatment helps them to live longer and improves their odds of remaining free of the disease, German researchers said on Friday.

Although tamoxifen has been the standard treatment following surgery for women with hormone sensitive tumours, they said changing to a newer class of drug called aromatase inhibitors improved overall survival.

"A lot of people have been waiting to see whether aromatase inhibitors will show a survival advantage, and I think these data will assure them that 5 years of tamoxifen is no longer the standard of care; the best treatment for women with hormone-sensitive early-stage breast cancer should include an aromatase inhibitor," said Professor Walter Jonat of the University of Kiel in Germany.

Aromatase inhibitors suppress the production of the hormone oestrogen, which is linked to the development of breast cancer, in post-menopausal women.

Tamoxifen works by preventing the action of oestrogen on the cells of the breast.

Jonat and his team combined information from earlier trials that compared the impact of taking tamoxifen for 5 years and switching to an aromatase inhibitor called anastrozole after 2-3 years on tamoxifen.

Anastrozole is made by AstraZeneca Plc under the brand name Arimidex.

"We showed that the benefits of switching to anastrozole in terms of disease and recurrence-free survival that have been seen in the individual trials translate into a significant benefit in overall survival," Jonat said in the study published online by The Lancet Oncology journal.

There were also fewer serious adverse side effects in women taking the newer drug. Tamoxifen has been associated with an increased risk of cancer of the lining of the womb while aromatase inhibitors may raise the risk of fractures.

The charity Breast Cancer Campaign said the findings were encouraging.

"While a cure for everyone may still be out of our reach, a move towards breast cancer being a life-long manageable condition could well be around the corner," said Pamela Goldberg, the chief executive of the charity.

Breast cancer is the most common cancer in women with more than one million cases diagnosed worldwide each year. A family history of the disease, early puberty, late menopause, delaying childbirth or not having children are risk factors.

Jonat said further questions such as which drug should be given first, how long the treatment should be taken and whether other drugs might produce better results, need to be answered.

But he added the findings confirm that doctors should consider switching older breast cancer patients who have taken tamoxifen for 2-3 years to anastrozole.