A STUDY that researchers are describing as a milestone
in breast cancer treatment has found a new class of drugs is more effective than
existing medication in preventing the disease recurring.
The findings, to be announced at a cancer conference in
Switzerland this morning, will pressure health officials to review treatments
for the disease, Australian researchers involved in the study said yesterday.
The trial, known as the Breast International Group 1-98 study, is one of the
largest breast cancer trials ever conducted, involving 8000 women, including
more than 800 from Australia and New Zealand.
The results show the drug letrozole, sold as Femara, is more successful at
preventing the recurrence of breast cancer in the five years after surgery than
Tamoxifen, the most commonly used drug.
John Forbes, professor of surgical oncology at the University of Newcastle
and a member of the international steering committee for the trial, said it was
one of the most significant breakthroughs he had seen in the past 25 years.
"Other milestones included finding out that giving any form of drug treatment
after surgery was effective. That was about 25 years ago and led to millions of
lives being saved," he said.
"Another was when we found out in the early 1980s that not everyone needed to
have a mastectomy."
The trial involved post-menopausal women with hormone-sensitive breast
cancer, which represents about 70 per cent of breast cancer cases in Australia.
Letrozole works by reducing the production of estrogen, depriving cancer
cells of the source of the hormone.
It is the second drug belonging to a new class of anti-cancer drugs called
aromatase inhibitors that has been proven to be more effective than Tamoxifen.
Last month a study of 9000 women published in the medical journal The Lancet
found that the drug Arimidex, also an aromatase inhibitor, prolonged
disease-free survival by 13 per cent and reduced cancer spreading to other parts
of the body by 14 per cent compared with Tamoxifen.
"Despite the success of Tamoxifen for 25 years, there are a substantial
number of patients who continue to have relapses from breast cancer despite
taking Tamoxifen," Professor Forbes said.
Breast cancer recurs in about 10 to 12 per cent of post-menopausal women
within five years after surgery. "Letrozole is about 20 per cent better,"
Professor Forbes said.
Another Australian involved in the research, Royal Hobart Hospital's director
of medical oncology Ray Lowenthal, said the findings were extremely significant.
"It's a very positive finding. It tells us this class of drug is very
effective for reducing breast cancer recurrence."
However, Arimidex and Femara are listed on the government-funded
Pharmaceutical Benefits Scheme only for the treatment of advanced breast cancer,
not for early breast cancer.
source: The Australian
