Prophylactic Double Thermal Ablation After Endoscopic Mucosal Resection of Large Non-Pedunculated Colorectal Polyps — ABLATION  

Colorectal Cancer Clinical Trial

Official title: Prophylactic Double Thermal Ablation After Endoscopic Mucosal Resection of Large Non-Pedunculated Colorectal Polyps: A Randomized Controlled Trial - (ABLATION Trial)

Status Not yet recruiting

Clinical Trial Summary

Large (≥20mm) colorectal polyps often harbor areas of advanced neoplasia, making them immediate colorectal cancer (CRC) precursors. Such polyps have to be completely removed to prevent CRC and to avoid surgery and/or adjuvant therapy. The laterally spreading lesions (LSLs) are removed via endoscopic mucosal resection (EMR). However, recurrence is common. Recent studies have found that the use of hybrid argon plasma coagulation (h-APC) for the ablation of the margin and base of resection post-EMR could significantly reduce the recurrence rate, and complete closure of the post-EMR defect can prevent other adverse pre- and post-procedure outcomes such as bleeding.

It is hypothesized that hypothesize that performing hybrid argon plasma coagulation (h-APC) margin and base ablation post-EMR for large (≥20mm) colorectal LSLs will demonstrate a lower recurrence rate compared to Snare Tip Soft Coagulation (STSC) margin ablation. It is also hypothesized that performing complete closure of the EMR defect will result in lower rates of adverse events compared to cases where no defect closure is performed.

Clinical Trial Description

This is a prospective, randomized controlled trial enrolling patients with non-pedunculated colorectal polyps ≥ 20mm who are referred for endoscopic mucosal resection (EMR). All primary EMRs will be randomized to either EMR with hybrid argon plasma coagulation (h-APC) ablation of the base and margins or EMR with Snare Tip Soft Coagulation (STSC) margin ablation groups. Additionally, each group will be randomized to either complete defect closure or not.

Patients will be enrolled in the study before the endoscopy procedure, or in the outpatient clinic.

Eligible patients who have consented to participate in the study will be asked to take a standard colonoscopy preparation regimen before their scheduled procedure.

EMR intervention will be performed for all eligible patients with a large laterally spreading lesions (LSLs) by expert endoscopists. Only if a polyp meets inclusion criteria, the study subject will be enrolled and randomized into one of these four groups:

• Group 1: EMR + h-APC margin and base thermal ablation

• Group 2: EMR + STSC of the margin

The standard EMR technique will be used for the primary removal of all polyps. Submucosal injection will be used to lift the polyp from the muscularis propria. Injection will be used as per the current standard of care using a contrast agent and a lifting agent (e.g., NaCl 0.9% or Voluven). Snare electrocautery resection will be facilitated until complete visible removal of the complete polyp. Electrocautery snare technique will be facilitated using standard microprocessor-controlled electrocautery. If residual polyp tissue cannot be removed by a snare, other means such as cold snare (i.e., for small residual polyp tissue that cannot be engaged into standard snares) or avulsive methods will be used. After the complete removal of the polyp, depending on the randomization group, h-APC or STSC techniques will be used for margin and base or only margin ablation of the post-EMR defect.

The polypectomy site will be tattooed with submucosal injection of approximately 1-2cc of India ink (standard of care to mark lesions) to allow recognition of the polypectomy site during follow-up endoscopy. Polyps will be sent to the pathology lab and evaluated according to standard practice by institutional pathologists. To determine the homogeneity and depth of h-APC margin ablation in the pathology lab, some ablated margins might be resected using the standard cold snare technique.

Telephone calls at 20-30 days following the EMR will be conducted to assess possible adverse events.

Follow-up 1: Surveillance colonoscopy at 6 months (± 2 months) after the EMR intervention for the assessment of recurrence (biopsy from the post-EMR site to be confirmed by pathology) following the intervention (h-APC) and the control (STSC) techniques.

Follow-up 2: Surveillance colonoscopy at 18 months (± 2 months) after the EMR intervention for the assessment of recurrence (biopsy from the post-EMR site to be confirmed by pathology) at FU1.

Patients with visible recurrence at the EMR site will undergo additional resection for complete eradication of recurrence. Patients with no visible but pathology-confirmed recurrence will be rescheduled for another colonoscopy with subsequent treatment of the post-EMR site and another follow-up colonoscopy for biopsies and confirmation of complete/incomplete eradication within 18 months after the initial EMR. ;

Related Conditions & MeSH terms

• Colonic Polyps
• Colorectal Cancer
• Polyp of Colon
• Polyps

• NCT number: NCT06271941
• Study type: Interventional
• Source: Centre hospitalier de l'Université de Montréal (CHUM)
• Status: Not yet recruiting
• Phase: N/A
• Start date: June 1, 2024
• Completion date: April 1, 2028