FRIDAY, July 11 (HealthDay News) -- The accuracy of predicting one's chances of developing breast cancer do not seem to improve even with the recent findings of some genetic markers for the disease, a new report says.

Scientists have identified seven single nucleotide polymorphisms (SNPs) that indicate a small but statistically significant increase in the risk of developing breast cancer. But when applied to existing models that use clinical factors, such as age and family history, to predict an individual's risk, they do not appear to change the prediction, according to a study in the July 8 online issue of the Journal of the National Cancer Institute.

Someone who is at high risk for breast cancer may choose to pursue more aggressive preventive strategies than a person at low risk, who may suffer side effects that far outweigh the benefits.

In the current study, Dr. Mitchell Gail of the National Cancer Institute found that adding the seven SNPs to the Breast Cancer Risk Assessment Tool (BCRAT) makes no improvement in the prediction accuracy. The BCRAT uses a woman's age, age at first menstruation and at birth of first child, family history of breast cancer, and breast biopsy results to predict her risk of disease to obtain its prediction.

"Experience to date and quantitative arguments indicate that a huge increase in the numbers of case patients with breast cancer and control subjects would be required in genome-wide association studies to find enough SNPs to achieve high discriminatory accuracy," Gail said in a prepared statement.

More information

The American Cancer Society has more about the risks of developing breast cancer.

SOURCE: Journal of the National Cancer Institute, news release, July 8, 2008