Newly funded treatment for postmenopausal women with hormone dependent advanced breast cancer

Postmenopausal women diagnosed with advanced breast cancer now have another treatment choice in the management of this disease.

This follows the listing of Arimidex (anastrozole) on the Pharmaceutical Benefits Scheme this month for the treatment of hormone-dependent advanced breast cancer in post-menopausal women.

Professor John Boyages, Executive Director of the New South Wales Breast Cancer Institute, has welcomed the increased availability of anastrozole for this group of women.

“We have seen advances in breast cancer treatments over the years but we are always looking for more effective and better tolerated treatments,” Professor Boyages said.

“With anastrazole, we have taken another step forward with women now having access to a further treatment option in tackling this disease.”

An analysis of two randomised double-blind trials compared the efficacy and tolerability of anastrozole against tamoxifen, the current standard treatment, as first line therapy for advanced breast cancer in postmenopausal women.

One trial was conducted at 97 sites in the United States and Canada, and the other at 83 sites in Australia, New Zealand, Europe, South Africa and South America.

“Results from the studies showed that anastrozole was at least as effective as tamoxifen in postmenopausal women with advanced breast cancer,” said Professor Boyages.

“However, in women whose tumours were hormone receptor positive, anastrozole provided greater benefit in delaying progression of the disease.”

Both treatments were well tolerated, however there were fewer serious side effects, such as deep vein thrombosis, in women treated with anastrozole.

Almost 10,000 women are diagnosed with breast cancer each year in Australia and nearly three out of four are past the menopause.

Oestrogen is responsible for stimulating tumour growth in around 75% of all cases of breast cancer in postmenopausal women.

In these women (whose oestrogen levels have dropped with the cessation of monthly ovulation) the production of oestrogen is driven by aromatase, an enzyme or “chemical messenger” found in fatty tissues.

Anastrozole, an aromatase inhibitor, works specifically by blocking the action of the enzyme aromatase, thereby reducing hormone dependent tumour growth.

Anastrozole was also approved earlier this year for the indication of early stage breast cancer in postmenopausal women with oestrogen/progesterone receptor positive disease, but is not yet available on the PBS for this indication. An application has been submitted for PBS listing of anastrozole for use as adjuvant treatment in early breast cancer in postmenopausal women.

Prior to PBS listing, the available options for accessing anastrozole for early breast cancer include private prescription or insurance.