Hereditary Cancer Assay Improves Colon Cancer Testing

Patients with a family history of colon cancer also are vulnerable to other cancers including breast, ovarian, endometrial and stomach cancer.

The detection of individuals with mutations associated with hereditary colon cancer greatly increases the chances of successful medical management in those at-risk individuals, which will save lives and reduce the downstream healthcare costs.

Scientists at Myriad Genetics, Inc. (Salt Lake City, UT, USA) have announced new clinical data from a study with myRisk Hereditary Cancer test. The assay is a 25-gene hereditary cancer panel that showed a 60% increase in mutations detected in cancer predisposition genes in patients with a prior history of colon cancer and/or polyps. Once a patient has been identified as carrying a deleterious mutation that patient's family members can be tested to determine if they have an increased risk of cancer.

The investigators also evaluated the mutation prevalence among cases referred for Lynch Syndrome (LS), the most common genetic cause of colon cancer, using the myRisk Hereditary Cancer test. The study presents data from two cohorts representing a total of 1,133 patients diagnosed with colon cancer or colorectal polyps. The results demonstrated that 10% of patients had deleterious mutations in the traditional hereditary colon cancer genes, but an additional 6% had deleterious mutations in other genes. This represents a 60% increase in the number of patients detected with deleterious mutations in cancer predisposing genes.

The scientists additionally investigated the overlap of personal and family histories in hereditary breast and ovarian cancer (HBOC) and hereditary colon cancer in 9,000 patients. Results showed that among patients tested for HBOC, 6.9% also had family histories that meet the National Comprehensive Cancer Network (NCCN, Fort Washington, PA, USA) criteria for hereditary colon cancer. In addition, 30% of patients tested for hereditary colon cancer also met NCCN criteria for HBOC. This analysis demonstrates the overlap among patients with a family history of hereditary breast cancer and those with a family history of colon cancer, suggesting that patients may benefit from multigene panels to better improve the diagnosis of hereditary cancer syndromes.

Richard J. Wenstrup, MD, the chief medical officer of Myriad, said, “The new data presented is ground breaking and underscores the importance of using multigene panels when testing patients for hereditary colon cancer. Importantly, the data suggest that the use of a 25-gene hereditary cancer panel significantly improved the detection of mutations and is a more efficient way for patients to receive appropriate medical management.” The studies were presented at the Annual Meeting Collaborative Group of the Americas on Inherited Colorectal Cancer (CGA) held October 7–8, 2013, in Anaheim (CA, USA).

Related Links:
Myriad Genetics
US National Comprehensive Cancer Network