AGA Recommends Lynch Syndrome Screening for Colorectal Cancer Patients

All colorectal cancer patients should be screened for Lynch syndrome, according to new guidelines from the American Gastroenterological Association (AGA). Findings of a study, published in Gastroenterology, outline the recommendations, conclusions, and ideas for moving forward.

“Approximately 50,000 Americans are expected to die from colorectal cancer this year, and hereditary syndromes account for a small, but important fraction of those diagnoses,” Joel H. Rubenstein, MD, AGAF, lead author of the guideline, research scientist at the Veterans Affairs Center for Clinical Management Research and associate professor, division of gastroenterology at the University of Michigan Medical School, explained in a press release. “The majority of patients with Lynch syndrome are unaware that they have the syndrome. The AGA recommendation for tumor testing in all newly diagnosed cases of colorectal cancer to identify Lynch syndrome could be considered as a process measure to ensure that patients are receiving the highest quality of care.”

For patients with a family history of Lynch syndrome, but no personal history of cancer, the AGA recommends that physicians offer patients the option of risk prediction modeling for testing in lieu of taking no action. Additionally, physicians can offer this population prediction modeling for testing instead of going directly to germline testing, the AGA said.

If patients have colorectal cancer, the tumor should be tested either with immunohistochemistry (IHC) or for microsatellite instability (MSI). The Lynch syndrome tumors, the AGA said, display high MSI.

The AGA added that for patients with colorectal cancer with IHC absent for MLH1 – of whom approximately 75 percent of whom will have sporadic cancers rather than Lynch syndrome – the tumors should be tested for BRAF mutation or hypermethylation of the MLH1 promoter. If the patient displays neither, germline tested should be conducted for Lynch syndrome.

For patients with Lynch syndrome, there are several options that physicians and specialists can offer. For example, the patient can undergo surveillance colonoscopy, instead of taking no action.

Furthermore, the patient can undergo surveillance colonoscopy every one or two years instead of less frequent or more spaced out intervals. Finally, aspirin can be offered as cancer chemoprevention.

To supplement these recommendations, the AGA also offered an online clinical decision support tool and a patient guideline summary.

The AGA estimates that about a third of colorectal cancer patients have a family history of the disease and that Lynch syndrome is the most common inherited cause of colorectal cancer. Lynch syndrome is found in about 700,000 Americans; though the majority of patients are unaware they have it.

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