Newly diagnosed colorectal cancer patients are recommended to partake in genetic testing of their tumors by the U.S. Multi-Society Task Force on Colorectal Cancer, which recently compiled a new guideline for cancer patients. The task force focused on recommendations about surveillance and management of the genetic condition Lynch syndrome, the most common cause of inherited colorectal cancer, which affects up to 4,000 new people every year only in the United States.
Regarding genetic testing, the recommendations recall that from the 143,000 people diagnosed with colorectal cancer annually in the U.S., more than 25% have familial risk of colorectal cancer. Therefore, the universal genetic testing of tumors for evidence of mismatch repair (MMR) deficiency of newly diagnosed patients to identify Lynch syndrome “have less than optimal sensitivity and specificity,” is “cost effective for the diagnosis” of the condition, and has “has greater sensitivity for identification of Lynch syndrome compared with other strategies, including Bethesda guidelines, or a selective tumor testing strategy,” as stated by the Task Force.
Germline genetic testing is able not only to confirm a diagnosis of Lynch syndrome, but also to determine the status of at-risk family members in families in which disease mutation has been found and to direct the management of affected and unaffected individuals. It is recommended for individuals who show evidence of MMR deficiency, the gene mutation in the family, who meet clinical criteria for the syndrome, or who have personal risk of more than five percent of having the syndrome.
Regarding the management of the syndrome, the Task Force reminds that patients suffering from Lynch syndrome are at more susceptible to developing colorectal cancer, as well as other cancers, reason why patients should start an annual history, physical examination, and patient and family education regarding the risk of cancer, between the ages of 20 and 25 years old.
Lynch syndrome may be treated either by removing the large intestine, during a colectomy with ileorectal anastomosis, a procedure that removes the large intestine and attaches the small intestine to the rectum. That is the primary treatment for patients who have colon cancer or precancerous colon polyps that cannot be removed by colonoscopy, however, a less extensive surgery can be considered for patients older than 60 to 65 years of age. On the other hand, there is also available an aspirin therapy, which is preventive.
Composed by gastroenterology specialists with a special interest in colorectal cancer, representing the American Gastroenterological Association, the American College of Gastroenterology and the American Society for Gastrointestinal Endoscopy, the U.S. Multi-Society Task Force on Colorectal Cancer compiled the “Guidelines on Genetic Evaluation and Management of Lynch Syndrome: A Consensus Statement by the US Multi-Society Task Force on Colorectal Cancer,” which was published in Gastroenterology, the official journal of the AGA Institute; American Journal of Gastroenterology, the official journal of ACG; Diseases of the Colon & Rectum, the official journal of ASCRS; andGIE: Gastrointestinal Endoscopy, the official journal of ASGE.