Broader Genetic Testing May Improve Breast Cancer Risk Assessment

To improve breast cancer risk assessment, providers should perform genetic testing in women who aren’t at high risk of developing the disease, according to a study published in The New England Journal of Medicine.

Researchers noted that hereditary cancer genetic testing has typically been available only for a specific population of women.

"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," said Fergus Couch, PhD, a Mayo Clinic pathologist.

Additionally, current estimates of breast cancer risk provided to women who are found to have a breast cancer mutation are appropriate only for those at high risk – not for women from the general population.

For the 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 US population-based studies.

Analyzing women from these population-based studies enabled researchers to better understand how frequent mutations were among various breast cancer genes. The analysis also helped researchers 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," said Couch. "When we looked at all women, we found that 30 percent of breast cancer mutations occurred in women who are not high-risk."

Prior to this study, women who were not high risk weren’t able to receive accurate estimates of their breast cancer risk. These findings were also similar among white, black, and Hispanic women.

Researchers believe that breast cancer clinics can use the new risk estimates to offer more accurate risk assessments for women who don’t have a family history of breast cancer.

“This study provides estimates of the prevalence and risk of breast cancer associated with pathogenic variants in known breast cancer–predisposition genes in the US population,” researchers concluded.

“These estimates can inform cancer testing and screening and improve clinical management strategies for women in the general population with inherited pathogenic variants in these genes.”

In the last few years, the healthcare industry has seen a push for broader cancer genetic testing as mounting evidence points to its effectiveness.

In 2018, a study showed that screening the general population for breast and ovarian cancer gene mutations through genetic testing is more cost-effective than screening only high-risk patients.

Researchers who conducted the 2018 study noted that testing only high-risk individuals is only moderately effective when it comes to identifying mutations and ruling out the absence of one.

“We and others have shown that this approach misses more than 50 percent of mutation carriers,” the researchers stated. “Personalized cancer prevention can have a much bigger impact on reducing the burden of disease but requires a shift in focus to the unaffected population.”

In an effort to enhance risk assessment, some healthcare organizations have introduced genetic testing and genomic sequencing as part of routine clinical care operations.

Geisinger Health System made the leap in 2018, and subsequently found more opportunities to identify patients at risk of developing certain conditions – including breast cancer.

“There are guidelines for many of the genes that we're testing for, particularly for some of the breast cancer genes. If somebody had a family history of breast cancer and they themselves have breast cancer at a young age, there are guidelines that say this person should be offered genetic testing,” Christa Martin, PhD, FACMG, director of the Autism & Developmental Medicine Institute at Geisinger, told HealthITAnalytics in an interview. 

“What we're finding from our study, and others are confirming this as well, is that more than 50 percent of patients who have these genetic changes don't have that family or personal history that fit those guidelines and warrant testing in a traditional clinical setting.”

As genomics and genetic testing become more prevalent in healthcare, leaders will be able to continually improve patient risk assessments and care management.

“With these screening tests, we can get ahead of disease and monitor patients. We'd rather keep our patients healthy than treat them once they show signs of illness. This type of screening program allows doctors to identify high-risk individuals that they might not otherwise identify through traditional genetic testing models,” Martin said.