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Significant Underuse of Critical Post-Diagnosis Genetic Test Among Colorectal Cancer Patients

MMR Deficiency Testing has Implications for Treatment, Prognosis, and Risk of Future Cancers

November 9, 2017

PHILADELPHIA (November 9, 2017)Although it is recommended for all colorectal cancer patients, most are not being screened for a common genetic syndrome that increases the risk of several forms of cancer and can influence treatment outcomes, according to a new study in JAMA Oncology. In the largest U.S. study of its kind, researchers at Fox Chase Cancer Center studied compliance with DNA mismatch repair (MMR) deficiency testing with a focus on younger patients, and with a goal of understanding why so many are not screened despite the recommendation.

The researchers found that only 28 percent of adult colorectal cancer patients undergoing colorectal cancer resection were reported to have MMR deficiency testing performed on their tumors, including 43 percent of those ages 18-49. Testing is especially important for younger patients, because that group has an increased incidence of Lynch syndrome. MMR deficiency or its absence can impact treatment decisions and outcomes for colorectal cancer patients, and individuals and their family members who have this mutation may be at risk for additional malignancies. Colorectal cancer is the second leading cause of cancer-related death in men, and the third-leading cause of cancer-related death in women.

“MMR deficiency is a characteristic feature of Lynch syndrome, and while Lynch syndrome causes only about 2-3 percent of colorectal cancers, MMR deficiency is estimated to affect as many as 15 percent of colorectal cancer patients,” said Michael Hall, MD, associate professor, Department of Clinical Genetics at Fox Chase and an author of the paper. “MMR deficiency status is a marker of good prognosis and can help us guide treatment recommendations.” The National Comprehensive Cancer Network updated its guidelines in 2014 to recommend screening for all colorectal cancer patients; previously the guidelines recommended screening only those patients whose family history suggested increased risk for MMR deficiency.

“This test tells physicians whether they must develop a prevention and early detection plan to reduce a patient’s risk for subsequent cancers associated with Lynch Syndrome,” said Nestor F. Esnaola, MD, MPH, associate director of Cancer Health Disparities and Community Engagement and professor of surgical oncology at Fox Chase. “Furthermore MMR deficiency testing helps identify patients who may not benefit from certain types of chemotherapy, but may experience a benefit from immunotherapy.”

The authors said that non-compliance with the screening guideline is a pervasive problem. Their research identifies groups least likely to be screened and factors that contribute to underuse of the test, which may be valuable in planning interventions to encourage wider use.

Esnaola, Hall, Talha Shaikh, MD, and their team were recognized with an American Society for Clinical Oncology (ASCO) Conquer Cancer Foundation Merit Award earlier this year.  

       

The Hospital of Fox Chase Cancer Center and its affiliates (collectively “Fox Chase Cancer Center”), a member of the Temple University Health System, is one of the leading cancer research and treatment centers in the United States. Founded in 1904 in Philadelphia as one of the nation’s first cancer hospitals, Fox Chase was also among the first institutions to be designated a National Cancer Institute Comprehensive Cancer Center in 1974. Fox Chase researchers have won the highest awards in their fields, including two Nobel Prizes. Fox Chase physicians are also routinely recognized in national rankings, and the Center’s nursing program has received the Magnet recognition for excellence four consecutive times. Today, Fox Chase conducts a broad array of nationally competitive basic, translational, and clinical research, with special programs in cancer prevention, detection, survivorship and community outreach. 
For more information, call 1-888-FOX CHASE or (1-888-369-2427).