Advance in breast cancer treatment: Older women with early breast cancer should
be put on a different drug from the current gold standard, say experts [BBC
News]
Older women with early breast cancer should be put on a different drug from the
current gold standard, say experts.

Five-year data in the Lancet show anastrozole is better at preventing the
spread and return of cancer than tamoxifen in postmenopausal women.

Such women should be put on the drug immediately and any on tamoxifen switched,
the authors recommend.

At about 1,000 pds a year compared to 20-30 pds for tamoxifen, it could be some
time before anastrozole is free on the NHS.

Earlier trial results of anastrozole (Arimidex) versus tamoxifen suggested the
newer drug would be superior in some women.

Tamoxifen is still a good treatment option for many women with breast cancer,
however.

First line therapy

Currently, women with breast cancer that is responsive to hormonal treatment
and who have gone through the menopause are advised to take tamoxifen for five
years.

However, tamoxifen can have side effects, including cancer of the womb lining
and blood-clotting disorders, and there is still a chance that the breast
cancer can spread or return.

Anastrozole is approved for use in any such woman who is unable to take
tamoxifen therapy because she has a high risk of experiencing these side
effects.

The ATAC trial findings now suggest that the drug should be used by all
postmenopausal women with hormone-responsive breast cancer.

In the trial, more than 9,000 such women with cancer confined to the breast
were given either tamoxifen or the aromatase inhibitor anastrozole for five
years.

Compared with tamoxifen, anastrozole increased disease-free survival by over
10% and increased the time to cancer recurring by around 20%.

It also reduced the chance of the cancer spreading around the body or occurring
in the other breast by 14% and over 40%, respectively.

The women taking anastrozole had fewer side effects, although they did report
more bone fractures and joint pain than the women taking tamoxifen.

Both anastrozole and tamoxifen work by interfering with the female hormone
oestrogen.

Tamoxifen prevents the growth-promoting action of oestrogen on breast cells by
blocking a molecule called the oestrogen receptor.

Anastrozole shuts down the production of oestrogen.

Lead investigator Professor Anthony Howell, from the Christie Hospital NHS
Trust in Manchester, said earlier results had suggested that it was reasonable
to switch patients currently on tamoxifen to an aromatase inhibitor.

"However, these new data from the ATAC trial suggest that it is not appropriate
to wait to start an aromatase inhibitor.

Licence change?

"The higher rates of recurrence, and the increased numbers of adverse events
and treatment withdrawals associated with tamoxifen, lend support to the
approach of offering the most effective and well tolerated therapy at the
earliest opportunity."

Dr Sarah Rawlings of Breakthrough Breast Cancer said: "This is welcome news for
postmenopausal women with early stage breast cancer of this type.

"However we would add a note of caution as currently Arimidex is not fully
licenced in the UK as an alternative to tamoxifen, and women should not be
discouraged from continuing with tamoxifen as it is the best option currently
available.

"Any woman concerned about their treatment for breast cancer should discuss it
with their doctor."

Liz Cheesman of Breast Cancer Care said: "It may be some time until the license
for anastrozole as a first line treatment is reviewed in the UK and the
treatment becomes available for women.

"The challenge facing health professionals is to look at how using anastrazole
as a first line treatment compares to other recent trial results showing the
benefit of using aromatase inhibitors following tamoxifen as extended
treatment."

The study findings will be presented at the San Antonio Breast Cancer Symposium
taking place in Texas, the US, this week.