Is the Double Channel Gastroscope Useful in Endoscopic Mucosal Resection for Large Sessile Colon Polyps?

colon polyps are less than 1 cm in size. However, en-doscopists often encounter large sessile colon polyps greater than 2 cm in practice. Removal of a large sessile colon polyp is difficult due to a high rate of procedure-related complications , such as bleeding and perforation. Therefore, patients with large sessile colon polyps are referred to a tertiary hospital for appropriate treatment. There are two usual endoscopic treatments for large sessile colon polyps: conventional endoscopic mucosal resection (EMR), and endoscopic submucosal dissection (ESD). ESD using various knives was initially introduced for the treatment of early gastric cancer, but has recently, been used for large sessile colon polyps. Theoretically, ESD is preferable to en bloc resection for better pathologic evaluation. However, because of high complication rates, ESD is not widely used for the treatment of large sessile colon polyps. Despite the advent of gastric ESD, piecemeal EMR is more widely used than ESD in such polyps. In Western countries, because of the technical difficulty and longer procedure time of ESD, piecemeal EMR is still the gold standard therapy for large sessile colon polyps >20 mm in diameter. 1 Although many endoscopists are performing colonic EMR, little attention has been paid to reducing the procedure time, which can be a very important issue in high-volume centers. Longer procedure times may influence the work of physicians and other personnel in the endoscopy room. One study reported that the total procedure time for EMR in patients with large sessile colon polyps (2 cm or larger) averaged 51.4 minutes (standard deviation, 25.6). 2 The mean size of the polyps was 34.2 mm, the perforation rate was 1.1%, and the post-EMR bleeding rate was 7.3%. Procedure time was measured from endoscope insertion to examination completion. In another large-scale study on ESD for large colon polyps, the mean procedure time was 116 minutes, with a mean tumor size of 35 mm; perforation occurred in 4.9%, and postoperative bleeding in 1.5%. 3 In this issue of Clinical Endoscopy, Voudoukis et al. 4 present their experience with large (>2 cm) sessile or flat left-sided colon polyp resection, focusing on the benefits of the double channel (DC) gastroscope for EMR. In their retrospective series , they compared the procedure time using a DC gastro-scope to that for a standard colonoscope or gastroscope (OS). They measured the EMR procedure time from first submuco-sal injection to just following polyp resection. This measurement …