'Surprisingly low' percentage of patients with cancer undergo germline genetic testing
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Identification of inherited genetic mutations that elevate cancer risk and may be susceptible to targeted therapies has transformed oncology care.
Despite guidelines that recommend genetic testing for most patients with cancer, a surprisingly small proportion of patients undergo such testing, study results published in JAMA showed.
“I have had a clinical practice in oncology and cancer genetics for the last 2 decades, and have had the privilege of watching inherited genetic testing results become increasingly essential to cancer treatment and prevention,” lead author Allison W. Kurian, MD, professor of epidemiology and population health at Stanford Medicine, told Healio. “However, my clinical experience has been that not all patients who should receive genetic testing are doing so. Thus, my colleagues and I wondered whether there are gaps and disparities in genetic testing at the population level.”
Researchers used SEER registries in California and Georgia to identify more than 1.3 million patients diagnosed with cancer between 2013 and 2019.
Results showed only 6.8% underwent germline genetic testing within 2 years of diagnosis.
Kurian characterized this as a “surprisingly low” rate.
Testing rates varied by cancer type, ranging from 50% for male breast cancer, 38.6% for ovarian cancer, 26% for female breast cancer, 6.4% for endometrial cancer, 5.6% for pancreatic and colorectal cancers, 1.1% for prostate cancer and 0.3% for lung cancer.
Kurian spoke with Healio about the findings and their potential long-term implications.
Healio: How did you evaluate the prevalence of germline genetic testing for patients with cancer?
Kurian: We collaborated with principal investigators of the state cancer registries of Georgia and California, which contribute to the NCI SEER program for tracking cancer incidence and mortality. The results of clinical genetic testing are not routinely reported to cancer registries, so we worked with the clinical laboratories that provide such testing to link results to state cancer registry data at the individual patient level.
Healio: What did you find?
Kurian: We found a remarkably low rate of genetic testing overall. Only 6.8% of adults diagnosed with cancer in 2013-2019 underwent testing. Genetic testing rates were highest for male breast cancer (50%) and ovarian cancer (38.6%); however, clinical practice guidelines recommend that 100% of these patients be tested, so there is a substantial gap. Further, we found persistent racial and ethnic disparities, with less testing receipt and more uncertain results among Asian, Black and Hispanic patients compared with non-Hispanic white patients.
Healio: Why do you think so few patients underwent guideline-recommended germline genetic testing?
Kurian: We did not have the opportunity to ask patients or physicians in this study why genetic testing did or did not occur. However, in our prior work, we found that one reason women with breast cancer did not undergo clinically indicated genetic testing was because their physicians did not recommend it to them. Although the cost of testing has dropped to around $100 to $250, that still may be a barrier for some patients. There also are structural barriers, including a shortage of genetic counselors and uncertainty as to how best to integrate genetic testing into oncology practice.
Healio: What are the potential implications of the findings?
Kurian: We hope these findings will lead clinicians and health care systems to address the potential barriers I mentioned — for example, explicitly recommending genetic testing when it is clinically indicated, and facilitating access through timely patient referral and/or other institutional pathways. There also is an urgent need to test and implement novel approaches to delivery of genetic testing after a cancer diagnosis, including a genetic testing station model, telemedicine and other emerging strategies.
Healio: Do you plan to conduct additional research in this area?
Kurian: We plan to study what happens after genetic testing — how the results of genetic testing are managed in terms of cancer treatments, secondary cancer screening and prevention, and cascade genetic testing of family members. Together with Steven Katz, MD, MPH, and Lawrence An, MD, at University of Michigan, I am co-leading a randomized clinical trial of new approaches to genetic testing of the family members of patients with cancer.
For more information:
Allison W. Kurian, MD, can be reached at Stanford University School of Medicine, Alway Building, M121M, 300 Pasteur Drive, Stanford, CA 94305; email: akurian@stanford.edu.
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