The purpose of this study to evaluate and examine whether use of Hybrid Argon Plasma Coagulation (APC) as an adjunct to endoscopic mucosal resection (EMR) will reduce the risk of residual or recurrent neoplasia at 6 months. Hybrid APC is an existing FDA approved device used to assist with ablation of abnormal tissue anywhere in the GI tract.

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.

Inclusion Criteria:

• Adult patient aged ≥18 and ≤89 of any gender, ethnicity and race referred to endoscopy for resection of large colon polyps
• Patients with a ≥20mm colon non-pedunculated polyp
• Ability to give written informed consent

Exclusion Criteria:

• Patients with known (biopsy proven) invasive carcinoma in a potential study polyp
• Pedunculated polyps (as defined by Paris Classification type Ip or Isp)
• Patients with ulcerated depressed lesions (as defined by Paris Classification type III)
• Patients with inflammatory bowel disease
• Patients who are receiving an emergency colonoscopy
• Poor general health (ASA class>3)
• Patients with coagulopathy with an elevated INR ≥1.5, or platelets <50
• Poor bowel preparation
• Target sign or perforation during initial EMR
• Need for ESD for complete resection prior to APC
• Pregnancy

Participant population was 10% (n=4) African American and 90% (n=36) with 100% (n=40) non-Hispanic/Latino population

At 30 days following the initial resection, the research coordinator called each patient to assess for any signs of post-procedural adverse events.

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.