THE first fall in the number of new breast cancer cases in more than 20 years has been linked with a sharp decline in the use of hormone replacement therapy.

According to a research paper in the Medical Journal of Australia, breast cancer cases among Australian women aged 50 or over fell by 6.7 per cent or 600 diagnoses between 2001 and 2003, coinciding with a sharp fall in HRT use.

The decline in usage followed a 2002 US study showing that women using the treatment to reduce the impact of menopause faced an increase in heart disease, strokes and cancer.

Karen Canfell of the Cancer Council of NSW, which completed the study with the Australian National University, said HRT prescriptions dropped by 40per cent between 2001 and 2003.

“Breast cancer incidence rates in women aged 50 years and older, who comprise the majority of HRT users, increased up to 2001,” she said. “But after 2001, incidence rates in this age group fell, corresponding to the drop in use of HRT.

“Incidence rates were significantly lower in 2003, equivalent to 600 fewer breast cancers.

“By contrast, there was no change in breast cancer incidence among women younger than 50, who rarely use HRT.”

Dr Canfell said the authors of the study had done their best to rule out all other possible explanations for the decline.

More than 100,000 Australian women are fighting breast cancer, with 13,000 new cases diagnosed each year and 2600 deaths annually. About 85 per cent of women are expected to survive breast cancer.

Cancer Council of NSW chief executive Andrew Penman described the findings as great news for women. He said other factors such as family history, fertility and breastfeeding were difficult for a woman in her 50s to do anything about. “But anyone can stop taking a tablet,” he said.

He said regulatory bodies should review the use of HRT. Risks increase rapidly if HRT is taken for more than five years.

Genevieve Knapp, 62, a retired nurse from Fairlight in Sydney, was diagnosed with breast cancer in 2002. She had been on HRT for four years and was having regular cancer checks.

To her horror she found cancer in both her breasts, which have now been removed.

“As a nurse, looking at my history, I knew this was out of the ordinary,” she said. “If it was just one tumour I might have assumed I had just fallen in to the one in eight women who get breast cancer. But I got two, while I was on HRT.”

She said even before the US research was released, she instinctively believed her cancer had been caused by HRT.

Credit: John Stapleton