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Researchers surveyed 1,063 women with early stage breast cancer who
had genetic tests between 2013 and 2015, a period when testing
evolved from focusing on two genes - BRCA1 and BRCA2 - to examining
a dozen or more genes that play a role in breast cancer.
The newer tests have been slow to catch on, in part because many
doctors are concerned about how women might react to the results,
researchers note in JCO: Precision Oncology.
"There are concerns that more ambiguous findings from more extensive
testing versus BRCA only testing may lead to unnecessary patient
worry and unwarranted aggressive interventions," said lead study
author Dr. Steven Katz of the University of Michigan in Ann Arbor.
"Indeed, some have argued that multi-gene panel (MGP) testing should
not replace BRCA1/2-only testing, even in patients with higher
pre-test risk of a pathogenic mutation, because of these concerns
about testers' negative reactions and the potential for
overtreatment."
Overall, 11 percent of the women in the study said worrying about
cancer made a big impact on their life, and 15 percent said they
were often or almost worried. But how much this worry impacted their
life and how often it happened didn't appear to vary based on
whether women got older two-gene tests or newer multi-gene tests.
"We found that test type (more versus less extensive testing) or
test results did not foment strong patient worry about future
cancer," Katz said.
"This finding is reassuring that MGP testing does not appear to
cause harm with regard to patient overreactions to test results,"
Katz said by email.
About 60 percent of the women in the study had the older genetic
tests that only looked for BRCA1 and BRCA2 gene mutations, while
about 40 percent had the newer multigene tests.
With newer multi-gene tests, it's more likely a patient will have a
positive test or a variant of unknown significance, the study
authors note. This means women have something unusual happening but
that doctors don't necessarily know how the abnormalities impact
cancer risk.
Virtually all of the patients surveyed received some form of genetic
counseling, which may have helped them prepare emotionally for
whatever the results might bring.
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"Availability of genetic counselors to explain potential results
prior to testing helps patients to make a well-informed decision
regarding the choice to pursue testing, and the timing of testing,"
said Dr. Lisa Newman, chief of the division of breast surgery at
Weill Cornell Medicine/New York Presbyterian Hospital Network in New
York City.
"Pre-test counseling can also address other factors that may
influence this decision, such has cost and how or whether to share
test results with relatives," Newman, who wasn't involved in the
study, said by email.
The study wasn't a controlled experiment designed to prove whether
or how the decision to get genetic tests, the type of test or the
results might directly impact the outcome of cancer treatment or
women's degree of worry about their diagnosis.
Still, the results should reassure doctors and patients that women
will be able to handle results from newer multi-gene tests as well
as they could with the older BRCA tests.
"I think that the majority of our patients are quite sophisticated
when it comes to processing the information that we provide, as long
as we take the time to discuss relevant issues thoughtfully and
empathetically," Newman said. "Explaining the fact that we have made
advances with genetic testing and therefore have a broader panel of
tests to offer is one example of a relevant issue; patients that
appear to be at risk for harboring hereditary susceptibility for
cancer have a right to be informed of these testing options."
SOURCE: http://bit.ly/2szAMgK JCO: Precision Oncology, online
December 19, 2018.
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