Canadian-led study shows 42 per cent reduction of breast cancer risk with
use of hormone replacement therapy in postmenopausal women with BRCA1
TORONTO, Sept. 23 /CNW/ - New Canadian-led research published today in
the Journal of the National Cancer Institute suggests hormone replacement
therapy is associated with a 42 per cent reduced risk of breast cancer in
postmenopausal women with a BRCA1 gene mutation.
In Canada, it is estimated 6000 women carry a BRCA mutation, which means
they have an 80 per cent chance of developing breast cancer in their
lifetime.(i),(ii) However, this risk is greatly reduced by surgically removing
the ovaries before menopause(iii), because ovary removal significantly
decreases the amount of estrogen and progesterone circulating in the body
(breast cancers need these hormones to grow.)
This preventive surgery (ovary removal) has become the standard of care
in North America and Western Europe for preventing both breast and ovarian
cancer for women with BRCA1 mutations, but only 54 per cent of women in Canada
with the gene mutation have this surgery performed.(iv) The reluctance is
because hormone therapy is perceived to increase the risk of breast cancer,
even though it is used to alleviate the effects of surgical menopause.
"The results of the study should be reassuring for women with a BRCA1
mutation who want to remove their ovaries before menopause to reduce their
risk of developing breast and ovarian cancer, but are concerned about the
effects of the hormone replacement therapy," said Steven Narod, M.D., Canada
Research Chair in Breast Cancer & Program Director of the Familial Breast
Cancer Research Unit at the Women's College Research Institute and professor
of Public Health Sciences at the University of Toronto. "This new information
can provide some reassurance to women when they are making this tough decision
about reducing their risk."
The study observed a total of 472 postmenopausal women with a BRCA1
mutation. They came from 55 cancer research centres in nine countries. Half of
the women were diagnosed with breast cancer. They were then matched and
compared to a similar group of women with a BRCA1 mutation, but with no breast
cancer diagnosis. Current age, age at menopause onset and the type and length
of hormone therapy treatment were all considered in the analysis. Women
without breast cancer were found to have used hormone replacement therapy more
often than women with cancer.
About Women's College Hospital
For the past 100 years, Women's College Hospital has been dedicated to
groundbreaking advances in women's health. Women's College Hospital
collaborated in the invention of the Pap test, opened Ontario's first regional
Sexual Assault Care Centre and was the first hospital in the province to use
mammography. Today Women's College Hospital is Ontario's first and only
ambulatory care centre and is a teaching hospital affiliated with the
University of Toronto focused on state-of-the-art care, research and education
in women's health.
About Women's College Research Institute
The Women's College Research Institute (WCRI) is Canada's largest
research institute dedicated solely to women's health and is part of Women's
College Hospital. WCRI is grounded in three principles: increasing knowledge
in women's health, advancing women's health by connecting researchers,
students and clinicians, and sharing knowledge with health care providers,
policy-makers and the public. In the 10 years since its creation, WCRI has
been leading breakthrough research in key areas of women's health, including
genetics and cancer, obstetrics, osteoporosis and more.
For more information about Women's College Hospital or the Research
Institute, visit www.womenscollegehospital.ca
(i) Ford D, Easton DF, Stratton DF, Narod S, Goldgar D, Devilee P.
Generic heterogeneity and penetrance analysis of the BRCA1 and
BRCA2 genes in breast cancer families. The Breast Cancer Linkage
Consortium. Am J Hum Genet. 1998;62:676-689.
(ii) Antoniou A, Phararoah PD, Narod S, et al. Average risks of breast
and ovarian cancer associated with BRCA1 or BRCA2 mutations
detecting in case series unselected for family history; a combined
analysis of 22 studies. Am J Hum Genet. 2003;72:1117-1130.
(iii) Eisen A, Luninski J, Klijn J, et al. Breast cancer risk following
bilateral oophorectomy in BRCA1 and BRCA2 mutation carriers: an
international case-control study. J Clin Oncol. 2005;23:7491-7496.
(iv) Metcalfe KA, Lubinski J, et al. International variations in rates
of uptake of preventive options in BRCA1 and BRCA2 mutation
carriers. Int J Cancer. 2008;122:2017-2022.
For further information:
For further information: Jilda Lazer, Environics Communications, (416)
969-2737, email@example.com; Sue Janzen, Women's College Hospital, (416)
323-6400 ext. 4054, firstname.lastname@example.org