TORONTO, June 4, 2011 /CNW/ - A large international Canadian-led
clinical trial investigating a new way to prevent breast cancer in
women at increased risk of developing the disease has found that the
drug exemestane reduces this risk by 65 per cent compared with placebo.
The results were presented today at the annual meeting of the American
Society of Clinical Oncology and published online by the New England Journal of Medicine.
With funding from the Canadian Cancer Society, the NCIC Clinical Trials
Group (CTG) led the trial which tested the drug exemestane, a member of
a class of drugs called aromatase inhibitors. Drugs in this class
suppress estrogen production, a key component in the development of
some types of breast cancer.
"The results are extremely exciting because they have the potential to
impact thousands of women," says Dr Michael Wosnick, Vice-President of
Research, Canadian Cancer Society. "We know that breast cancer takes a
tremendous toll on Canadian women and their families. The results of
this study offer an important new option to prevent this devastating
disease in women who are at higher risk for it."
The NCIC CTG MAP.3 (ExCel) trial followed more than 4,500
post-menopausal women from Canada, United States, Spain and France over
a five-year period. All study participants were at increased risk for
developing breast cancer. Risk factors include a woman's age, her
family history of breast cancer, her age at first menstrual period and
her age at her first child's birth. The study is the first randomized
trial to determine if an aromatase inhibitor can be used to prevent
breast cancer in healthy women.
At a median follow-up of three years, study researchers found that the
group of women receiving exemestane had a 65% reduction in invasive
cancers (11 invasive breast cancers in the exemestane group compared to
32 in the placebo group). Additionally, the researchers found fewer
cases of pre-cancerous lesions in the group receiving exemestane.
The patient story
Vi Siemens and her three sisters have always been close and that
relationship has been strengthened by their desire to do their part in
preventing breast cancer. They have been participating in this landmark
trial, sharing the daily bond of taking a pill and going for six-month
The sisters lost their mother and two aunts to breast cancer so are only
too aware of the risk they face. But they did not hesitate in their
decision to join the trial.
"It wasn't a tough decision for me to participate at all," says Siemens.
"All you have to do is look to the left or the right. Everybody knows
somebody who's had breast cancer in their family. Somebody has to test
Vi and her sisters know that they are part of something that can make a
difference for themselves, for their family and for women everywhere.
"You're thinking about the next generation," says Vi. "You'd like to do
something more than in just your own corner."
This trial is just one of three conducted by the NCIC CTG and funded by
the Canadian Cancer Society which this year has been selected as "Best
of ASCO". The other two studies include a landmark breast cancer
prevention trial and one which found a more effective way to treat
prostate cancer. Studies featured in Best of ASCO have the potential to
change clinical practice around the world.
Breast cancer is the most common cancer among Canadian women (excluding
non-melanoma skin cancer). In 2011, an estimated 23,400 women will be
diagnosed with breast cancer and 5,100 will die of it.
The NCIC Clinical Trials Group is a national research program of the
Canadian Cancer Society and receives programmatic funding, including
for this trial, from the Canadian Cancer Society Research Institute.
Additional support for the trial was provided by the Canadian
Institutes for Health Research and Pfizer.
The Canadian Cancer Society fights cancer by doing everything we can to
prevent cancer, save lives and support people living with cancer. Last
year, the Society funded more than $48 million in leading-edge research
projects across the country. When you want to know more about cancer,
visit our website at cancer.ca or call our toll-free bilingual Cancer Information Service at 1-888
SOURCE Canadian Cancer Society (National Office)
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For more information or interviews with Dr Michael Wosnick or Vi Siemens please contact: