Study may help better assess the risk of breast cancer in women without a family history

A new multi-institution study led by Fergus Couch, Ph.D., a Mayo Clinic pathologist, provides more accurate estimates of breast cancer risk for U.S. women who harbor inherited mutations in breast cancer predisposition genes. The findings of the CARRIERS Consortium study, which were published Wednesday, Jan. 20 in the New England Journal of Medicine, may allow health care providers to better assess the risk of breast cancer in women - many of whom have no family history of breast cancer - and provide more appropriate risk management strategies.

Traditionally, genetic testing of inherited breast cancer genes has focused on women at high risk who have a strong family history of breast cancer or those who were diagnosed at an early age, such as under 45 years."

Dr. Fergus Couch, Ph.D., Mayo Clinic Pathologist

He says current estimates of breast cancer risk provided to women when they are found to have a breast cancer mutation are actually appropriate only for those who are at high risk and not for women from the general population.

In the CARRIERS Consortium study, researchers conducted hereditary cancer genetic testing of 12 established breast cancer genes in 32,247 women with breast cancer and 32,544 women of similar ages without breast cancer from several large U.S. population-based studies. By analyzing women from these population-based studies, researchers were able to better understand how frequent mutations were among the various breast cancer genes and more accurately estimate the risk of developing breast cancer for women in the general population with mutations in those genes.

"The risk of developing breast cancer is generally lower for women without a family history of the disease" says Dr. Couch. "When we looked at all women, we found that 30% of breast cancer mutations occurred in women who are not high-risk." Dr. Couch says that before this study, these women were not able to receive accurate estimates of their breast cancer risk. He also noted that these findings were similar for white, black and Hispanic women.

Dr. Couch anticipates that breast cancer clinics will use the new risk estimates to provide more accurate risk assessments for women who don't have a family history of breast cancer.