Genetic variants don’t help predict breast cancer better

For years, doctors have relied on the traditional screening method known as the “Gail model”, which involves asking general questions based on woman’s conventional risk factors such as family history, medical history etc.

But with the onset of genotyping, a combination of these questions with genetic testing was deemed as the most reliable way to gauge a woman’s odds for developing the disease.

"It was not enough improvement to matter for the great majority of women," team leader Sholom Wacholder of the National Cancer Institute in Bethesda, Maryland, was quoted by Reuters as saying.

More than 11000 women studied
Researchers from the U.S. National Cancer Institute examined data from four large U.S.-based studies and one large Polish breast cancer study to come up with their findings.

The studies involved 11,588 women in the age group of 50-79. Of these, 5,600 women were diagnosed with breast cancer while 6,000 were healthy controls.

For the study, the researchers evaluated both the traditional risk factors using the “Gail model” as well 10 common genetic variants to see if they could help in predicting the breast cancer risk better than the traditional model.

They, however, did not look at BRCA-1 and BRCA-2 breast cancer genes, more malignant form of genetic mutations.

"These variants are common," noted study co-author Dr. Patricia Hartge, senior scientist and deputy director of epidemiology and biostatistics at the U.S. National Cancer Institute. The variants are known as SNPs -- single nucleotide polymorphisms.

Outcome of the study
On analysis, the researchers predicted the cancer risk in 58 percent of the patients using the traditional model. On the other hand, the estimated absolute risk rose modestly to 61.8 percent when the 10 genetic variants were also added to the traditional treatment.

Overall, it was found that the addition of genetic variants only helped a little in improving a doctor’s ability to predict the cancer risk.

"For women seeking advice on their personal risk of breast cancer, it is obviously too early to incorporate SNP testing into a counseling procedures, although such tests are already advertised for this purpose on the internet," the researchers wrote.

Findings of the study appear in the New England Journal of Medicine.