Breast cancer risks in women with a family history of breast or ovarian cancer who have tested negative for a BRCA1 or BRCA2 mutation
Author Information
Author(s): Metcalfe K A, Finch A, Poll A, Horsman D, Kim-Sing C, Scott J, Royer R, Sun P, Narod S A
Primary Institution: Lawrence S. Bloomberg Faculty of Nursing, University of Toronto
Hypothesis
What are the breast cancer risks for women with a family history of breast cancer who tested negative for BRCA1 or BRCA2 mutations?
Conclusion
Women with a significant family history of breast cancer but who test negative for BRCA mutations have approximately a four-fold risk of developing breast cancer.
Supporting Evidence
- 65 women developed breast cancer compared to an expected number of 15.2.
- The actuarial risk of breast cancer in the entire cohort was 0.7% per year.
- The SIR was highest for women under the age of 40 at 14.9.
- Women between 50 and 70 years had a higher absolute risk of 1% per year.
Takeaway
If your mom or sister had breast cancer, and you don't have the BRCA gene, you still have a higher chance of getting breast cancer than most people.
Methodology
The study followed 1492 women from families with a history of breast cancer who tested negative for BRCA mutations, collecting data on cancer status and calculating standardized incidence ratios.
Potential Biases
Selection bias may have occurred if the proband included only relatives with breast cancer.
Limitations
Cancers were self-reported and not confirmed by pathology; genetic testing was limited to the proband, and some BRCA mutations may have been missed.
Participant Demographics
Women from 365 families with a significant family history of breast cancer.
Statistical Information
P-Value
p<0.0001
Confidence Interval
95% CI=3.1–5.0
Statistical Significance
p<0.05
Digital Object Identifier (DOI)
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