Hot avulsion versus argon plasma coagulation for the management of the non-lifting polyp: a multicentre, randomised controlled trial

Endoscopic management of large colonic polyps is an increasingly utilised and accepted alternative to surgery. Complete polyp removal after a single treatment session is high with a recent prospective study reporting first-time success in 84% of patients presenting for endoscopic management. The success rate of first time complete polypectomy is significantly lower when the lesion cannot be fully excised utilising a standard injection and snare technique. This is more common in large rectal polyps, polyps that have undergone partial or incomplete resection, and polyps that have been marked with SPOT tattoo. All these scenarios result in submucosal fibrosis and therefore failed lift with standard submucosal injection. In this setting the traditional approach has been to resort to ablative techniques such as argon plasma coagulation (APC) and snare tip coagulation (STC), however the use of APC has been identified as a risk factor for residual adenoma at follow-up colonoscopy with a recent study showing an increase in residual adenoma at follow-up from 17.5 to 39.5% (RR 2.25; 1.45-3.50, p=0.002). Recently, the use of hot avulsion (HA) has been shown in a prospective pilot study, to be a safe and highly effective technique for dealing with difficult non-lifting polyps (NLP). Currently there is no published literature to guide effective management of the NLP. The proposed study design is a randomised clinical trial comparing HA to APC (the current standard of care) for the management of polyps that fail removal using a standard snare resection technique. We postulate that HA will result in a significantly higher rate of complete polyp removal of the non-lifting polyp when compared to standard therapy. Patients undergoing colonoscopy for removal of large polyps (>20mm), polyps that have failed previous resection, polyps that have previously been injected with SPOT tattoo or patients presenting for follow-up of previously removed large polyps will be approach for inclusion in the study. Following commencement of polypectomy, if the endoscopist fails to remove the polyp entirely using standard snare techniques, they will be randomised to either HA or standard of care (APC). The primary outcome measure of this study is the rate of macroscopic and histologic eradication of neoplasia at the first follow up colonoscopy which is routinely performed at 4 months. The outcome variable is dichotomous (residual or no residual) and will be expressed as a proportion. If patients fail removal at first follow-up, a second treatment will be attempted. If at the second follow-up there is persistent polyp, this will be considered a treatment failure and the treating physician will then be able to either cross arms or refer the patient for surgical management.