San Antonio, TX—Multiplex genetic testing in BRCA1/2-negative cancer patients with in-person genetic counseling allows informed decision-making while decreasing short-term anxiety, according to data presented at the 2015 San Antonio Breast Cancer Symposium.
Of 184 BRCA1/2-negative patients at the University of Pennsylvania with a personal or family history of breast or ovarian cancer, 166 completed pretest counseling with a certified genetic counselor, with 93% electing to move forward with multiplex testing, reported Angela R. Bradbury, MD.
“We found that knowledge increased after patients went through genetic counseling, and a number of people do make informed decisions,” she said.
For the study, 529 BRCA1/2-negative patients were approached in the clinic or mailed an introductory letter informing them of the opportunity for multiplex testing with Myriad myRisk, a 25-gene hereditary cancer panel with a focus on 8 primary cancer sites. The study used a tiered-binned counseling and informed consent model for multiplex testing.
“The key elements of the tiered-binned model [are] to provide the minimal information we feel people need to make an informed decision and then let them drive how much more in depth they need to go,” said Dr Bradbury, assistant professor of Hematology/Oncology, University of Pennsylvania Abramson Cancer Center, Philadelphia. “The reason to use that approach is that we don’t want to overwhelm people.”
To date, 184 consented to and 166 completed pretest counseling. Of these, 155 proceeded with testing while 9 declined and 2 are still considering testing.
Following pretest counseling, general anxiety scores declined from a mean of 6.5 to a mean of 5.8 (P <.05) on a scale ranging from 0 to 21. Genetic knowledge increased from a mean score of 66.0 to a mean of 68.1 (P <.05) on a scale ranging from 18 to 87.
Fifteen (11%) patients received a positive result on multiplex testing, and 44 (32%) had a variant of unknown significance (VUS).
When assessed by the type of result received, there were greater increases in genetic knowledge and short-term testing anxiety among carriers of a mutation. Perceived utility declined after pretest and posttest counseling but by significantly less among carriers. Those with a VUS had no evidence of increased uncertainty.
“In genetic medicine, there’s a fear that patients will become distressed by uncertainty,” said Dr Bradbury. “I won’t say that this is conclusive, but in ongoing studies, it appears that people have some tolerance and can understand uncertainty.”
One of the clinical utilities of genetic testing is its effect on patient management, she said. Medical management changed for 33% of carriers and 4% of those who received results in the current study.
Resource utilization also comes into play. “It is a high resource path to have genetic counselors for 2 visits,” she said. “Separate studies are looking at more efficient ways, such as using the telephone or even replacing genetic education counseling for that first visit with an online module. Right now, this is not the setting to do that because it’s more complex testing than just BRCA1/2 testing.”
In a survey conducted after completing pretest counseling, about 70% of the participants in the study said they were either not willing to receive or not sure about telephone counseling instead of in-person counseling. About one-third indicated a willingness for telephone counseling after both the pretest and posttest counseling.
Bradbury AR, Patrick-Miller L, Egleston BE, et al. Patient reported outcomes of multiplex breast cancer susceptibility testing utilizing a tiered-binned counseling and informed consent model in BRCA1/2 negative patients. Poster presented at: 2015 San Antonio Breast Cancer Symposium; December 5-8, 2015; San Antonio, TX. Abstract P2-09-01. http://sabcs15.posterview.com/nosl/i/P2-09-01. Accessed January 4, 2016.