By Megan Brooks
NEW YORK (Reuters Health) - Only a minority of women with ovarian or breast cancer undergo recommended genetic testing, a new study suggests.
Researchers examined data for about 77,000 women diagnosed with breast cancer and 6,000 diagnosed with ovarian cancer in 2013 and 2014. Only about 24% of breast cancer patients and 31% of ovarian cancer patients had genetic test results, the research team reports in the Journal of Clinical Oncology, online April 9.
"We initiated this study - the largest population-based study of multigene testing in breast and ovarian cancer patients - because we wanted to see what cancer genetic testing and results looked like in the real world," Dr. Allison Kurian of Stanford University in California said in a news release.
"Our major finding was substantial under-testing of ovarian cancer patients: fewer than one third were tested, while guidelines advise that nearly all should be tested. For breast cancer, guidelines have not recommended testing all patients and thus a rate of 24.1% is less concerning," Dr. Kurian told Reuters Health by email.
"It is crucial that doctors seeing ovarian cancer patients discuss genetic testing with them and facilitate their obtaining it, and that ovarian cancer patients and their relatives advocate for appropriate genetic counseling and testing in their care," she added.
When genetic tests were performed, 7.8% of women with breast cancer and 14.5% of those with ovarian cancer had pathogenic variants, information that "could be used to drive care decisions and influence family members' health care and screening choices," Dr. Kurian said in the release.
The study also found "concerning" disparities in genetic testing by race/ethnicity and insurance status.
For example, nearly 34% of non-Hispanic white women had genetic testing, compared with only about 22% of black women and 25% of Hispanic women. About 20% of Medicare patients were tested compared with about 34% of those with other forms of health insurance.
The prevalence of genetic was around 20% in areas where 20% or more of residents were poor compared with about 38% in regions with less poverty.
"More research is needed to understand all the factors contributing to this gap in care quality and how best to fix it," Dr. Kurian told Reuters Health.
The study did not have commercial funding. Dr. Kurian has received research funding from Myriad Genetics and has other relationships with Ambry Genetics, Color Genomics, GeneDx/BioReference, Invitae and Genentech.
J Clin Oncol 2019.