MedicalResearch.com Interview with:
Antonis Antoniou PhD
Reader in Cancer Risk Prediction
Academic Course Director MPhil in Epidemiology
Centre for Cancer Genetic Epidemiology
Department of Public Health and Primary Care
Strangeways Research Laboratory Cambridge
University of Cambridge
MedicalResearch.com: What is the background for this study? What are the main findings?
Response: Several studies demonstrated that women with genetic faults in the BRCA1 and BRCA2 genes are at increased risk of developing breast and ovarian cancer. Having accurate age-specific cancer risk estimates for women with mutations is essential for their optimal clinical management.
Most studies to date that estimated cancer risks for BRCA1 and BRCA2 mutation carriers have been “retrospective”, in other words they look at what happened in the past. Estimates from such studies are prone to biases because they rely on the experience of women who have already developed cancer and on self-reported cancer family history information on relatives – which may have inaccuracies.
The ideal epidemiological study design for estimating cancer risks are prospective studies. In prospective studies, healthy women with genetic faults are followed over time and overcome these potential biases. However, to date, published prospective studies have been very small.
In the present study we used data from a prospective cohort of women with BRCA1 and BRCA2 mutations who were recruited from 1997 to 2011 and were followed over time. The study included almost 10,000 women who were included in the analyses, and was made possible through collaborations between scientists from Europe, North America and Australia. The prospective study design explains why it has taken 20 years of hard work to get these results. Most importantly, it took an enormous long-term contribution and commitment from the women themselves to allow the scientists to be able to assemble this dataset.
Here, we were able to estimate more precisely the breast and ovarian cancer risks for women with faults in BRCA1 and BRCA2. These risk estimates will provide more confidence in the counseling and clinical management of women with faults in the BRCA1 and BRCA2 genes.
A novel finding in this study is that breast cancer risk for women with faults in BRCA1 and BRCA2 increases rapidly at a young age then remains at a constant high level for the rest of their lives. It peaks in the 40’s for BRCA1 mutation carriers and in the 50’s for BRCA2 carriers, but carriers of mutations in both genes are at about the same high risk in later life. This is important information to inform the clinical management of older mutation carriers.
This study also shows clearly that for women with a mutation, there are other factors that are important in modifying the breast cancer risk. The study has demonstrated that the extent of the woman’ family history of cancer and the exact place on the gene where her mutation is located are very important in determining the actual risk.