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ASBrS 2018: Breast Cancer Genetic Testing Guidelines Exclude Almost Half of High-Risk Patients

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Key Points

  • The patients who met NCCN testing guidelines criteria had a 10.2% pathogenic/likely pathogenic variant rate (36 of 353), and the patients who did not meet criteria had an 8.6% pathogenic/likely pathogenic variant rate (31 of 360).
  • An analysis of patients testing positive for BRCA1/2 variants found no statistical difference between Medicare qualifiers and nonqualifiers (3.3% vs 2.3%). Similar results were found when testing for other breast cancer–related mutations (9.6% vs 7.8%). 

Current restrictive genetic testing guidelines exclude many patients who harbor high-risk breast cancer mutations, according to two new studies presented at the American Society of Breast Surgeons (ASBrS) 19th Annual Meeting (Abstracts 402910, 404340). One study found that whether or not patients met National Comprehensive Cancer Network® (NCCN®) testing guidelines, they had a similar number of pathogenic mutations related to breast or other cancers. In a second study, Medicare patients who did not meet guidelines for BRCA1/2 testing also had similar rates of these genetic variants as those who qualified. In addition, study findings were consistent for other breast cancer–related mutations.

Strongly emphasizing the need for revised testing criteria, both authors note that guidelines predate today’s more sophisticated BRCA1/2 and multigene testing. They caution that most insurance providers model their coverage after these guidelines—usually recommending testing for BRCA1/2 only—and that many patients with inherited breast cancer risks are being missed.

Study Findings

Peter Beitsch, MD, of TME Breast Care Network, reported on early data from the organization’s Universal Genetic Testing Registry for patients with breast cancer who had no prior genetic testing. Participants underwent an 80-gene panel test for genetic variants that have a known association to breast and/or other cancers. The target accrual is 1,000 patients with 500 who meet and 500 who do not meet NCCN testing guidelines. Current accrual is 923 with 713 having testing and CRFs completed. The patients who met criteria had a 10.2% pathogenic/likely pathogenic variant rate (36 of 353), and the patients who did not meet criteria had an 8.6% pathogenic/likely pathogenic variant rate (31 of 360).

Dr. Beitsch commented, “There is no statistically significant difference between the pathogenic variant rate between patients who meet and who do not meet NCCN guidelines. Furthermore, the cost of expanded panel genetic testing has decreased to the point that economically-based guidelines for testing are no longer relevant.”

In a second study, genetic counselor Jennifer Axilbund, MS, CGC, of Invitae, examined 1,990 Medicare patients referred by physicians for BRCA1/2 and other optional breast cancer–related genetic testing. Of these, 1,516 (76.2%) met BRCA1/2 testing guidelines, while 474 (23.8%) did not. An analysis of patients testing positive for BRCA1/2 variants found no statistical difference between Medicare qualifiers and nonqualifiers (3.3% vs 2.3%). Similar results were found when testing for other breast cancer–related mutations (9.6% vs 7.8%). Ms. Axilbund stressed that under Medicare criteria, “almost half of all patients with actionable variant genes are missed.”

Both researchers note that test criteria screen more effectively for carriers of highly penetrant BRCA1/2 mutations than for other genetic variants—and that this is expected.

“These guidelines were created specifically to capture this group, and generally they do,” said Ms. Axilbund.  She noted that with the recent growth of genetic sequencing, however, the number of known breast- and overall cancer–related pathogenic variants increased dramatically, and test guidelines have not kept pace.

This broader genetic information can benefit patients and their families, who may share the same mutations, and allow more targeted breast cancer screening, surveillance and management. Dr. Beitsch noted, “Women do not need to be protected from their genetic health information. Genetic testing is the future of medicine, not just in patients with cancer, but all patients.” 

The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.


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