Hybrid APC Assisted EMR for Large Colon Polyps

Colon Cancer is a major disease that effects more than 1 million people per year globally. Adenomatous polyps have been identified as the main precursor leading to colorectal cancer. Colon cancer screening is the best way to detect and remove large, often asymptomatic polyps. Early detection and resection of these colorectal polyps can prevent the development of colon cancer. Endoscopic mucosal resection (EMR) is a technique used for resection of medium to large colon polyps. In this technique, fluid is injected into the submucosa creating a cushion between the mucosa and the muscularis propria. An electrocautery snare is then deployed to resect the polyp in a single (en-bloc) or multiple (piecemeal) pieces. Most polyps >2 cm are resected in piecemeal way. Although EMR is now considered standard of care with a successful resection rate of 85 % and low risk of complication (3-10% bleeding and 1% perforation), this technique has inherent deficiencies, especially piecemeal EMR. Recurrence rates following piecemeal EMR can be as high as 20%. Resection of scarred polyps using this technique is particularly challenging due to the non-lifting of the polyp. Endoscopic submucosal dissection (ESD) is an alternative approach that aims to remove non- pedunculated precancerous or cancerous lesions over 20 mm in one piece (en-bloc resection rate of 89.95% and lesion recurrence rate of 0.7%). However, due to its technical complexity and high complication risk (mainly bleeding and perforation, with complication rates approximately 8%), it is not the current standard of care and only performed by experts in the technique.

Hybrid Argon plasma coagulation (APC) is a new technique in which the endoscopist reinjects the submucosa with fluid to create a cushion (normal saline/ diluted adrenaline and /or sodium hyaluronate solution) to protect the muscle layer and then ablation is done using spray argon coagulation to treat any microscopic residual disease that is the seed for local recurrence. Previous studies have shown that this technique is a safe and easily applicable technique to complete resection for recurrent polyps after first EMR.

Investigators hypothesize that with Hybrid APC assisted EMR there will be a decrease in recurrence rate after 6 months and it will be more effective compared to the standard EMR procedure.

This is a pilot study in which patients with non-pedunculated large polyps ≥ 20mm undergoing endoscopic mucosal resection (EMR) will be recruited. Following standard EMR all patients will undergo adjuvant Hybrid Argon Plasma Coagulation (APC) of the base and edges of the polypectomy site to fulgurate any potential microscopic residual disease. Resected polyps will be sent to the pathology laboratory where pathologist determine the final diagnosis of the polyps as per standard of care.