Existing screening protocols in place are failing to identify patients who might be carriers of a genetic mutation that is linked to certain cancers, according to Mayo Clinic researchers.
Both hereditary breast and ovarian cancer and Lynch syndrome are significant risks for individuals who carry mutated BRCA1 and BRCA2 genes. Mutated versions of these genes also increase the risk of prostate and pancreatic cancer, according to the study published July 16 in JCO Precision Oncology.
The Mayo Clinic researchers evaluated genetic sequencing of more than 44,000 patients from a range of backgrounds. Of that group, they identified 550 carriers of the mutated genes. Around half of the 550 carriers did not know about the related genetic risks. In addition, 40% of the 550 carriers did not actually meet existing clinical guidelines for genetic screening.
"This study is a wake-up call, showing us that current national guidelines for genetic screenings are missing too many people at high risk of cancer," Niloy Jewel Samadder, MD, author of the study and Mayo Clinic gastroenterologist and cancer geneticist, said in the news release.
Patients with a BRCA1 mutation have a 60% risk of developing breast cancer and a 40% risk of developing ovarian cancer in their lifetime. This is slightly lower for patients who have a BRCA2 mutation. Their risk of developing breast cancer is 50% in their lifetime and 20% for ovarian cancer, with added risks to males with this gene for prostate and pancreatic cancers, according to the data.
Some genes also increase the risk of Lynch syndrome, with which patients who are diagnosed have an 80% risk of developing colorectal cancer in their lifetime.
"These results suggest the existing guidelines for genetic testing inadvertently introduce biases that affect who qualifies for testing and who receives coverage through health insurance. This leads to disparities in cancer prevention," Dr. Samadder said. "Our results emphasize the importance of expanding genetic screening to identify people at risk for these cancer predisposition syndromes."