Study Finds Low Rates of Germline Genetic Testing After Cancer Diagnosis in California and Georgia

By: Celeste L. Dixon
Posted: Monday, July 17, 2023

Far fewer patients undergo germline genetic testing than is recommended by practice guidelines, according to data analysis of the populations of adults diagnosed with cancer in California and Georgia between 2013 and 2019, although the screening rates did increase substantially over time, according to Allison W. Kurian, MD, MSc, of Stanford University, California, and colleagues. In a study reported in JAMA, the primary outcome was germline genetic testing within 2 years of a cancer diagnosis, and it was far from the ideal 100%. In fact, among the 1,369,602 patients diagnosed with cancer, just 93,052 (6.8%) completed the testing.

“We were surprised at the low rates of testing given the growing evidence for the benefits of results for patients and their families,” stated coauthor Steven Katz, MD, MPH, of the University of Michigan School of Public Health, in an institutional press release. “Testing patients can be the gateway to identify hereditary cancer risk in families and offer prevention and early detection strategies that can save lives.”

The number of patients tested certainly varied by cancer type, the researchers found. It ranged from 50% and 38.6% for male breast and ovarian cancers, respectively, to 26% for female breast, 6.4% for endometrial, 5.6% each for pancreatic and colorectal, 1.1% for prostate, and 0.3% for lung cancers.

In terms of racial disparities, Dr. Kurian and co-investigators found that compared with the 31% of non-Hispanic White patients with male breast, female breast, or ovarian cancers who underwent testing, patients of other races and ethnicities with the same diagnoses underwent testing less often: 22%, 25%, and 23% of Asian, Black, and Hispanic patients, respectively.

These differences were significant—P < .001—and warrant study to learn how these discrepancies can be narrowed, the team wrote. They also advocated for investigations into why patients with cancers linked to BRCA1/2 genes (breast and ovarian) are tested so much more frequently than those with cancers associated with Lynch syndrome (colorectal and endometrial).

Disclosure: The study authors’ disclosure information can be found at jamanetwork.com.

JAMA

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