NEW YORK (GenomeWeb) – A survey of breast cancer patients and their surgeons has found that many patients undergo genetic testing without seeing a genetic counselor and may not understand complex results.
Researchers led by the University of Michigan's Steven Katz found that about half of breast cancer patients with an average risk of disease, but who are found to harbor a variant of uncertain significance, undergo bilateral mastectomies. To them, this indicated that some clinicians and patients might not understand genetic testing results.
As they reported in the Journal of Clinical Oncology, Katz and his colleagues surveyed women diagnosed with breast cancer in 2014 and 2015 about their genetic testing experiences. They found that about half the women discussed their results with a genetic counselor. They also surveyed those patients' surgeons regarding how genetic testing results influence their management of patients, and found that many surgeons said they treated women with variants of unknown significance the same as they did patients with known cancer-causing mutations.
"Our findings suggest a limited understanding among physicians and patients of the meaning of genetic testing results," first author Allison Kurian from Stanford University Medical Center said in a statement. "Clinical practice guidelines state that variants of uncertain significance should not be considered to confer high cancer risk, and that patients with these variants should be counseled similarly to a patient whose genetic test is normal."
Katz, Kurian, and their colleagues surveyed 2,500 women diagnosed with breast cancer, 666 of whom underwent genetic testing. Of the women who received testing, 59 percent met the higher pre-test risk of carrying disease mutations.
Most of the women underwent genetic testing after being diagnosed, but before undergoing surgery. In particular, the researchers reported that 67 percent of the high-risk group and 64 percent of the average-risk group underwent testing after diagnosis, but before surgery. Fewer than 20 percent of women said that a genetic counselor ordered their test, despite guidelines advising pre-test counseling, the researchers noted.
For most, genetic testing revealed no mutation. But 7 percent reported that a BRCA1, BRCA2, or other known risk variant was found, while 9 percent reported that a variant of uncertain significance was discovered.
High-risk women with a pathogenic mutation were more likely to have a bilateral mastectomy, as were average-risk women with a pathogenic mutation. Just over half of average-risk women with a variant of uncertain significance had a bilateral mastectomy, the researchers added.
Katz, Kurian, and their colleagues also surveyed those women's surgeons, and received 377 responses.
Surgeons with a higher volume of patients said they had more confidence discussing genetic testing results with patients than those with a lower volume. However, surgeons with lower confidence in discussing results were also the least likely to refer patients to genetic counseling, the researchers reported, a result they found troubling. They noted, however, that it could be attributed in part to the shortage of genetic counselors in the US.
A minority of surgeons — some 17 percent of high-volume and 35 percent of low-volume surgeons — said they never delayed surgery to wait for test results, which the researchers, again, said was "concerning."
Half of the lower-volume surgeons and a quarter of the higher-volume surgeons said they managed patients with variants of uncertain significance within BRCA1 or BRCA2 the same as patients with known risk variants within those genes.
While the researchers noted that the decision to undergo a bilateral mastectomy is complex, they said their findings suggest that patients might not understand their results or that their test results did not influence their decision. This further indicated to the researchers that additional efforts are needed to bolster both surgeons' and patients' genetic knowledge.
"Our study highlights the urgent need for improved patient access to cancer genetics experts, particularly genetic counselors, and for educating physicians about the appropriate use of genetic testing and interpretation of test results," Kurian added.