Study findings improve accuracy of breast cancer risk estimates for women with no family history

A multi-institution study led by Fergus Couch, Ph.D. (PATH ’97), chair, Division of Experimental Pathology and Laboratory Medicine at Mayo Clinic in Rochester, provides more accurate estimates of breast cancer risk for U.S. women who have inherited mutations in breast cancer predisposition genes. The findings may allow health care providers to better assess the risk of breast cancer in women ― many who have no family history of breast cancer ― and provide more appropriate risk management strategies.

“Traditionally, genetic testing of inherited breast cancer genes has focused only on women at high risk who have a strong family history of breast cancer or those who were diagnosed at an early age,” says Dr. Couch.

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 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 get 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.