About one-half of patients with breast cancer with a clinically actionable genetic variant are missed by current testing guidelines, according to a new study in the Journal of Clinical Oncology.

“Approximately 330,000 patients are diagnosed with breast cancer every year in the United States. An estimated 10% of these cancers likely result from hereditary causes,” Peter D. Beitsch, MD, surgeon at the Dallas Surgical Group and colleagues wrote. “Studies have estimated that less than 10% of all BRCA1 and BRCA2 carriers have been identified.”

​Genetic mutation. Source: Getty

Previous studies found that 50% to 80% of at-risk individuals have not received genetic testing, which may be due to guidelines from the National Comprehensive Cancer Network (NCCN). Insurance companies use these guidelines to determine reimbursement.

Beitsch and colleagues studied 959 consecutive patients from 20 community and academic centers with breast cancer to determine if the appropriate patients were receiving genetic screening.

Overall, 49.95% met 2017 NCCN criteria to undergo genetic testing and 50.05% did not.  

All patients underwent germline genetic testing for a multicancer panel of 80 genes, including BRCA1/2. In total, 8.56% of patient had a pathogenic or likely pathogenic (P/LP) variant, where 9.39% of those who met NCCN guidelines had a P/LP variant compared with 7.9% of those who did not meet criteria.

The difference between the groups was not statistically significant (P = .4241).

“The results of our study suggest that a strategy that simply tests all patients with a personal history of breast cancer would almost double the number of patients identified as having a clinically actionable genetic test result,” the researchers wrote. “Advances in [next generation sequencing] technologies have dramatically reduced the cost of BRCA1/2 testing and enabled simultaneous sequencing and deletion/duplication testing of BRCA1/2 concomitantly with dozens of additional risk genes for breast, ovarian, and/or other cancers (eg, PALB2, PTEN, ATM, CHEK2).”