New breast cancer findings from University of Toronto described
March 2nd, 2009
2009 MAR 2 -- "Genetic testing for mutations in BRCA1 and BRCA2 is available in Canada for women with a significant family history of breast cancer. For the majority of tested women, a BRCA1 or BRCA2 mutation is not found, and counselling regarding breast cancer risk is based on the review of the pedigree," scientists in Toronto, Canada report.
"In this prospective study, we estimate breast cancer risks in women with a family history of breast cancer and for whom the proband tested negative for a mutation in BRCA1 or BRCA2. Families with two or more breast cancers under the age of 50 years, or with three cases of breast cancer at any age, and who tested negative for a BRCA1 or BRCA2 mutation were identified. Follow-up information on cancer status was collected on all first-degree relatives of breast cancer cases. The standardised incidence ratios (SIRs) for breast cancer were calculated by dividing the observed numbers of breast cancer by the expected numbers of breast cancers, based on the rates in the provincial cancer registries. A total of 1492 women from 365 families were included in the analyses. The 1492 first-degree relatives of breast cancer cases contributed 9109 person-years of follow-up. Sixty-five women developed breast cancer, compared to 15.2 expected number (SIR = 4.3). The SIR was highest for women under the age of 40 (SIR = 14.9) years and decreased with increasing age. However, the absolute risk was higher for women between the age of 50 and 70 (1% per year) years than for women between 30 and 50 (0.4% per year) years of age. There was no elevated risk for ovarian, colon or any other form of cancer. Women with a significant family history of breast cancer (ie, two or more breast cancers under the age of 50 years, or three or more breast cancers at any age), but who test negative for BRCA mutations have approximately a four-fold risk of breast cancer," wrote K.A. Metcalfe and colleagues, University of Toronto.
The researchers concluded: "Women in these families may be candidates for tamoxifen chemoprevention and/or intensified breast screening with an MRI."
Metcalfe and colleagues published their study in British Journal of Cancer (Breast cancer risks in women with a family history of breast or ovarian cancer who have tested negative for a BRCA1 or BRCA2 mutation. British Journal of Cancer, 2009;100(2):421-425).
For additional information, contact K.A. Metcalfe, University of Toronto, Lawrence S Bloomberg Faculty Nursing, Toronto, ON, Canada.
The publisher's contact information for the British Journal of Cancer is: Nature Publishing Group, Macmillan Building, 4 Crinan St., London N1 9XW, England.
Keywords: Canada, Toronto, Breast Cancer, Breast Carcinoma, Gynecology, Oncology, Ovarian Cancer, Ovarian Carcinoma, Women's Health, University of Toronto.
This article was prepared by Clinical Oncology Week editors from staff and other reports. Copyright 2009, Clinical Oncology Week via NewsRx.com.
