Fewer Than One in Ten Cancer Patients Undergoes Genetic Testing, Large Study Finds
Up to 10% of cancer cases may be caused by genetics. Among the most common cancer-linked genetic mutations are those in the BRCA1 and BRCA2 genes. These can increase the risk of breast cancer in both men and women, ovarian cancer, and prostate cancer, among others. A new study finds that despite these risks, most people are not getting recommended testing for genetic mutations after being diagnosed with cancer. This can keep the patient and their loved ones in the dark about their health risks and may get in the way of better treatments.
A study recently published in the Journal of the American Medical Association gauged the rate of germline genetic testing among more than 1.3 million cancer patients diagnosed in Georgia and California between 2013 and 2019. Overall, only 6.8% underwent the testing within two years of diagnosis. The researchers say this is a “surprisingly low rate” and these tests are very important.
Dr. Allison Kurian, lead author and professor of epidemiology and population health at Stanford University, says, “When we’re talking about cancer risk, germline genetic testing looks specifically at the genes that, if altered in a way that is harmful, give people a much higher risk of cancer than the average person.
“Increasingly, we’re seeing that germline genetic testing matters in terms of selecting a medication or surgical treatment that might be best for a patient.”
The team found the testing was also lower than it should have been for cancers that have higher testing recommendations. Among male breast cancer patients, the rate was 50%, despite a strong link between this form of the disease and inherited gene mutations. Ovarian cancer, which is often deadly, had a rate of 38.6%. Dr. Kurian notes that testing should be universal for patients with both of these forms of cancer. Female breast cancer patients, meanwhile, tested at a rate of 26%.
There were also racial and ethnic disparities found. White patients with male breast, female breast, and ovarian cancer had a 31% testing rate, while Black patients had a rate of 25%, Asian patients a rate of 22%, and Hispanic patients tested at a rate of 23%. Non-white patients were also more apt to have uncertain results, likely owing to less research being done within those populations to better understand mutations.
Dr. Kurian says, “Uncertain results are more common in populations and groups of people who haven’t had as much access to testing because we haven’t gotten a sense of the full range of what’s normal for those populations. It’s all about whose genes were sequenced and defined as normal.”
The research didn’t investigate the cause of the lower rates, but the team says it may have to do with doctors not advising patients to get tested. The researchers believe tests and results need to be integrated into cancer management and prevention.
To read the whole study, click here.
