Predictors of Unsuccessful Endoscopic Mucosal Resection of Complex Colon Polyps: "You Can Look But You Can't Touch"

Colon cancer is the third leading cause of cancer-related death in the United States. The number of these deaths has significantly decreased due to screening colonoscopies. A colonoscopy is a procedure in which a physician examines the rectum and large intestines for abnormalities through the use of a specialized camera called an endoscope. Colonoscopies decrease the mortality associated with colon cancer through two main ways: by detecting and removing pre-cancerous lesions called polyps; and by detecting colon cancer at earlier stage, when therapies can still be effective at treating or removing the cancer.

Most colon polyps are small and can be completely removed during a standard colonoscopy. However, there is a growing awareness amongst endoscopists of polyps that are too large or inaccessible to be safely removed during a routine colonoscopy. Previously, these lesions required surgery for removal of the affected part of the colon. There is a growing body of evidence that suggests these more complex colon polyps can be entirely removed endoscopically through a procedure called endoscopic mucosal resection (EMR), thereby avoiding costly and debilitating surgery. Given that it is a novel procedure, it is only available at specialized care centers.

EMR is a procedure identical to a colonoscopy, with more steps involved in the lifting and removal of complex polyps. As many as 80-90% of complex polyps can be successfully removed with EMR. However, it has been noted that removal of the polyp in pieces, rather than as a whole can result in a 20-30% recurrence rate at the resection site. Any manipulation of the polyp prior to EMR may impair the ability to fully remove the lesion. Some factors that have previously been suggested to increase the difficulty of EMR include previous dye injections, removal attempts, and polyp sampling. However, the true impact of previous manipulations of CCPs remains unclear.

This study aims to be one of the largest prospective, multi-centered studies investigating factors that predict the failure of EMR in the removal of complex colon polyps.