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Genetic Risk for Prostate Cancer

For Some Men, Results Can Be Confusing

Perron, Michelle

doi: 10.1097/01.COT.0000546182.01013.bf
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prostate cancer; genetic risk

prostate cancer; genetic risk

A genetic or familial risk for prostate cancer (PCa) may be present in 5-15 percent of U.S. men, and researchers are learning that conveying information about genetic results and cancer risk can be challenging and deserves attention (Prostate 2018; doi:10.1002/pros.23535). A survey conducted as part of the Genetic Evaluation of Men (GEM) study recently determined that confusion about the difference between genetic mutations and variants of uncertain significance (VUS) was notable among men with PCa or at genetic risk for it.

“Genetic test results can be complex, and patients need to discuss genetic results with providers who have expertise and can support understanding their results,” said Veda N. Giri, MD, Associate Professor in Medical Oncology and Cancer Biology and Director of Cancer Risk Assessment and Clinical Cancer Genetics at Sidney Kimmel Cancer Center (SKCC) at Jefferson Health in Philadelphia.

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Study Background

GEM is a prospective research registry and genetic testing cohort study led by SKCC. The goal of GEM is to optimize genetic testing and counseling strategies for men with prostate cancer through the collection of personal medical and cancer history data, family cancer data, exposure history, and biospecimens. The study is conducted in collaboration with Fox Chase Cancer Center in Philadelphia. Multiple analyses already have been performed as part of GEM, including a survey that identified a need to supplement genetic education and counseling with nutrition guidance and information (Nutrition Counseling Among Men Undergoing Genetic Counseling for Prostate Cancer, http://www.wk-prostatecancer.com/articles/nutritioncounseling.html).

In this study focused on multigene test results, researchers sought to determine knowledge of cancer risk and genetics—and particularly patient understanding of personal genetic testing results (Prostate 2018; doi:10.1002/pros.23535).

The survey sample included GEM participants with PCa or who were at high risk for PCa. Each participant received pretest genetic counseling in one of three ways: in person, via video with a handout, or via telehealth.

“During this counseling session, we discuss what genetic testing is—what it means to undergo testing, what it means to have an inherited risk for cancer, and what the results mean for men and their families,” Giri explained. “We talk about cancer risk factors and the knowns and unknowns of genetic testing. We provide all information we believe men need to make an informed decision to proceed with genetic testing.”

Before and after genetic testing, each participant completed a survey. The pretest survey gathered information about knowledge of PCa risk and genetics, as well as general literacy and numeracy. Genetic test results could be positive for a genetic mutation, negative for a genetic mutation, or a VUS. Results were delivered in the same manner that pretest counseling had been provided (in person, video plus handout, or via telehealth). After genetic testing, the post-test survey gathered information about knowledge of PCa risk and genetics, literacy, numeracy, and each patient's understanding of personal genetic test results.

Two hundred men were enrolled in the GEM clinical multigene testing study at the time this research took place. All were offered the opportunity to complete the survey at the pre- and post-test intervals, and 109 men did so.

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Study Results

The mean age of the respondents was 62.5 years. White men comprised 80.7 percent of the cohort; 83.5 percent of the cohort reported some college education or higher.

In terms of clinical status, 58.7 percent of the men had been diagnosed with PCa and 40.4 percent reported family history that met criteria for any of the three HCS diagnoses associated with PCa (hereditary breast and ovarian cancer, hereditary nonpolyposis colorectal cancer, hereditary PCa). Approximately 70 percent (71.6%) of the men reported a family history of PCa, and 47.7 percent reported a family history of breast cancer.

The survey findings contained some surprises in terms of patient understanding of personal genetic testing results. “While the majority of patients understood their personal results, there was a subset of men who didn't report their results properly,” Giri told Oncology Times.

On the post-test survey, 88 men responded correctly about their genetic test result and 13 responded incorrectly. These 13 men reported that they carried a genetic mutation—but their testing showed no mutation. Of particular note, 12 of these men reported they had a mutation when their genetic testing had identified a VUS. The researchers stated that “overall, having a VUS genetic test result was significantly associated with incorrectly reporting genetic test results (p < 0.001).”

The possibility of finding a VUS is discussed during all counseling about genetic testing results. “These are ‘gray’ findings that represent changes in genes that don't meet full criteria for mutation,” Giri said. “The fact that 13 men with VUS reported that they had a mutation is of concern. It means that they walked away thinking that they have a genetic mutation when they do not.”

In addition to identifying this misunderstanding of results by 13 men, the researchers found a signal that receiving genetic counseling via video and receiving genetic testing results by telephone were also associated with a lack of understanding about genetic test results (p=0.015). Family history of an HCS (p=0.039) and family history of breast cancer (p=0.017) were associated with accurate understanding and reporting of personal genetic test results.

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Next Steps

This study highlights the need for targeted strategies to reinforce understanding of genetic testing results, thus shaping patient experience, appropriate cancer risk management, and family support and follow-up. “This research shows that there is a need to develop more resources and to follow up with men to ensure that they understand their genetic testing results and thus their genetic risk,” Giri said. “It might mean that they need to [contact] a genetics professional by phone or in some other format.”

In response to these findings, GEM researchers are developing a web resource designed to meet the information needs of men with PCa risk and their families. Giri said the resource will contain detailed information on VUS, as well as genetic testing results that indicate a mutation is present. The target date for deployment of the online site is during Prostate Cancer Awareness Month in September.

“In addition to identifying a need for follow-up, this research showed the importance of genetic counseling,” Giri pointed out. “There is a great need for patients to understand their genetic testing results. We need concerted efforts to address what men need.”

Michelle Perron is a contributing writer.

Wolters Kluwer Health, Inc. All rights reserved.
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