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

The findings of the CARRIERS Consortium study, which were published Wednesday, Jan. 20, 2021 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," says Fergus Couch, Ph.D., a Mayo Clinic pathologist and leader of the multi-institution study. 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.

The CARRIERS consortium is a group of 17 large epidemiology studies in the U.S. focused on women in the general population who develop breast cancer. CARRIERS aims to improve understanding of genetic and environmental risk factors for breast cancer using information from the participants in these studies. CARRIERS is supported by National Institutes of Health grants R01CA192393 and R35CA253187, and the Breast Cancer Research Foundation.

A version of this article was originally published as a news release on the Mayo Clinic News Network.