Study finds 1 in 8 patients with cancer harbor inherited genetic mutations

PHOENIX, Ariz. ― Genetic testing can uncover inherited genetic mutations, and could individualize cancer therapies, improve survival, manage cancer in loved ones and push the boundaries of precision medicine.

In a new study published in JAMA Oncology, scientists with Mayo Clinic’s Center for Individualized Medicine conducted genetic testing in more than 3,000 patients who were diagnosed with cancer at Mayo Clinic Cancer Center locations in Arizona, Florida and Minnesota. In all, the scientists found that 1 in 8 patients with cancer had an inherited cancer-related gene mutation. This mutation would not have been detected in half of these patients using a standard guideline-based approach.

“We found that 13.5% of patients had an inherited mutation in a gene associated with the development of their cancer,” says Niloy Jewel Samadder, M.D., a Mayo Clinic gastroenterologist and hepatologist, who is the study’s author. “Everyone has some risk of developing cancer, and in most cases the disease develops by chance. However, some people are genetically predisposed to developing certain types of cancer, such as breast or colon cancers.”

A genetic mutation can cause a gene to malfunction and lead to a cell becoming cancerous. Although many mutations that cause cancer happen by chance in a single cell, the study confirms that nearly 10%-25% are inherited mutations that set off a cycle of events that can lead to cancer.

Niloy Jewel Samadder, M.D.

Dr. Samadder says uncovering these hidden inherited genetic mutations could lead to opportunities for cancer management in families and targeted cancer therapies that can save lives.

In the two-year Interrogating Cancer Etiology Using Proactive Genetic Testing (INTERCEPT) study, Mayo Clinic provided free genetic testing and counseling to 3,084 Mayo Clinic patients as part of their standard cancer care. The project, representing the largest known multicenter study of universal testing of patients with cancer, included a broad mix of cancer stages and types, including breast, colorectal, lung, ovarian, pancreatic, bladder, prostate and endometrial cancers.

The researchers were surprised to find that the standard guidelines physicians relied on to determine which patients with cancer should undergo genetic testing were only able to identify 48% of the patients with an inherited genetic mutation.

Watch: Dr. Samadder discusses the research findings.

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