By Neka Sehgal
Isolation of certain gene variants that boost the risk of breast cancer may be an effective treatment, but genetic screening offers only a slight edge over the conventional questionnaire in predicting the onset of the disease, finds a new study.
Lead authors David Hunter, Dean for Academic Affairs and Vincent L. Gregory Professor in Cancer Prevention at Harvard School of Public Health (HSPH) stated, “Unlike the situation for women with a strong family history of breast cancer, in which a search for rare disease-causing variants may be useful, for women without a strong family history breast cancer risk prediction based on common risk variants is currently of marginal utility.”
Among the existing methods to screen breast cancer in women is the ‘Gail model’, which takes into account traditional risk factors based on a series of questions about her age, medical history and the family’s history of cancer.
Analysis of data
The researchers from the National Cancer Institute analyzed 5,590 breast cancer patients and 5,998 healthy women aged 50 to 79 years from four U.S. cohort studies and one case-control study from Poland.
In a bid to determine how well genetic screening measured up to the Gail model in predicting the disease, researchers used information on traditional risk factors and 10 common genetic variants associated with breast cancer.
The ten common gene variants known as single nucleotide polymorphisms (SNPs) together are thought to account for less than 5 percent of breast cancer risk.
However, the powerful breast cancer genes known as BRCA1 and BRCA2 that are linked to a lifetime risk of breast cancer were excluded from the test.
Analysis revealed that the predictive accuracy of genetic screening for breast cancer was 59.7 percent whereas that of the question-based Gail model 58 percent. A combination of the two led to a predictive power of 61.8 percent.
Findings of the study
The researchers found the predictive accuracy of genetic screening for breast cancer was 59.7 percent whereas that of the question-based Gail model was 58 percent. A combination of the two led to a predictive power of 61.8 percent.
According to the researchers, using both genetic and the traditional questionnaire performed only slightly better than either model alone.
However, the marginal improvement does not make genetic screening, an expensive technique a viable clinical process.
Co-author of the study, cancer epidemiologist, Patricia Hartge of George Washington University in Washington D.C., stated, “Our results indicate that the recent identification of common genetic variants does not herald the arrival of personalized prevention of breast cancer in most women.
“Even with the addition of these common variants, breast-cancer risk models are not yet able to identify women at reduced or elevated risk in a clinically useful way.”
The study was conducted by investigators from the National Cancer Institute (NCI), part of the National Institutes of Health, and the Harvard School of Public Health.
The findings are published in the ‘New England Journal of Medicine’.
Source: The Money Times
