Colon Adenomas, Colon Adenomatous Polyp
Conditions
Brief summary
Margin thermal ablation after piecemeal EMR significantly reduces recurrence of large colorectal polyps. As recurrence rates are now low, the key implementation question relates to efficiency and reproducibility of different ablation techniques. This randomized controlled trial compares snare tip soft coagulation (STSC) with Hybrid APC (ERBE), with procedural time as the primary endpoint.
Detailed description
Piecemeal endoscopic mucosal resection (EMR) of large (≥20 mm) non-pedunculated colorectal lesions was historically associated with local recurrence rates in the range of 15-20% at first surveillance when no systematic margin therapy was applied¹. The introduction of structured post-EMR margin thermal ablation has substantially altered this landscape. In a landmark randomized controlled trial, systematic thermal ablation of the resection margin reduced recurrence from 21% to 5%². Subsequent prospective and multicenter studies performed in high-volume expert centers using standardized circumferential snare-tip soft coagulation (STSC) protocols have demonstrated further reductions, with reported recurrence rates approaching 1-2%³. Most recently, Gauci et al. demonstrated that complete margin thermal ablation eliminates lesion size as a risk factor for recurrence following piecemeal EMR of large non-pedunculated colorectal polyps, reinforcing the durability and consistency of this approach in contemporary practice⁴. These findings are supported by meta-analytic data confirming that thermal margin ablation significantly reduces recurrence compared with no ablation without increasing clinically meaningful adverse events⁵. Accordingly, current international guidelines strongly recommend routine thermal ablation of the post-EMR mucosal defect margin following piecemeal resection of large colorectal lesions⁶. Given that recurrence rates are now low when complete circumferential ablation is systematically performed, additional trials powered for recurrence would require prohibitively large sample sizes to detect incremental differences. The remaining clinically relevant gap therefore relates not to efficacy, but to procedural efficiency, reproducibility, and implementation, particularly in early-career or non-advanced interventional endoscopists. Snare-tip soft coagulation requires precise contact-based application of thermal energy at each point sequentially along the entire resection margin, demanding consistent tip positioning and repeated fine manipulations. This technical precision may be particularly challenging for endoscopists with limited experience, increasing the risk of incomplete ablation or prolonged procedural time. Hybrid APC (ERBE) delivers thermal energy via a non-contact argon plasma beam with a broader coagulation footprint per activation, potentially enabling faster and more reproducible circumferential coverage with fewer individual applications. The wider energy spread of Hybrid APC may therefore reduce operator-dependent variability and facilitate more consistent margin treatment, particularly in the hands of early-career endoscopists. Whether this translates into a meaningful reduction in net ablation time and improved completion rates compared with STSC has not been prospectively evaluated.
Interventions
PROCEDURESnare Tip Soft Coagulation (STSC)
Circumferential thermal ablation of the resection margin will be performed using the distal tip of a standard polypectomy snare in soft coagulation mode. The tip will be applied sequentially to the entire visible mucosal defect margin to achieve complete circumferential treatment.
PROCEDUREHybrid APC (ERBE)
Circumferential thermal ablation of the resection margin will be performed using Hybrid APC (ERBE) in standard APC mode. The argon plasma beam will be applied sequentially to the entire visible mucosal defect margin to achieve complete circumferential treatment. Electrosurgical settings will be standardized according to unit protocol (effect and wattage predefined for Hybrid APC use).
Sponsors
Western Sydney Local Health District
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
NONE
Eligibility
Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
No
Inclusion criteria
* Age ≥18 years * Undergoing piecemeal EMR of a non-pedunculated colorectal lesion ≥20 mm in size * Macroscopically complete resection achieved prior to margin ablation (no visible residual adenomatous tissue at the resection base) * Ability to provide written informed consent
Exclusion criteria
* Lesions requiring en bloc resection by ESD * Lesions with suspected deep submucosal invasion based on endoscopic assessment (e.g., depressed morphology, non-lifting sign, NICE type 3 pattern, or equivalent advanced imaging criteria) * Inflammatory bowel disease with active colitis at the lesion site * Overt invasive carcinoma requiring surgical management * Pregnancy * Inability to provide informed consent
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Net margin ablation time | during the procedure | Net margin ablation time (seconds), defined as the elapsed time from the first application of thermal energy to the resection margin (first activation in soft coagulation mode) until the operator declares completion of circumferential margin ablation. Time will be recorded using a standardized stopwatch method by a trained assistant/nurse (or captured from time-stamped video, if available). Interruptions unrelated to margin ablation (e.g., equipment troubleshooting) will be documented and excluded from net time where feasible, with sensitivity analyses planned. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Time (total) | during procedure | Total procedure time (minutes): from first endoscopic view of the lesion to scope withdrawal. |
| Technical success of margin ablation | during procedure | Technical success of margin ablation: completion of circumferential thermal treatment of the entire visible mucosal defect margin as judged by the supervising endoscopist and recorded as yes/no. |
| Instrument exchanges (count) | during procedure | Instrument exchanges (count): number of device exchanges required after completion of EMR to achieve margin ablation. |
| Need for additional haemostatic therapy (yes/no) | during procedure | Need for additional haemostatic therapy (yes/no): including clips, APC outside assigned intervention, injectable agents, or other modalities used for bleeding control. |
| Operator-rated ease of use (VAS 0-10) | during procedure | Operator-rated ease of use (VAS 0-10): recorded immediately post-procedure (0 = very difficult, 10 = very easy) |
| Operator confidence (VAS 0-10) | during procedure | Operator confidence (VAS 0-10): confidence that ablation was complete (0 = not confident, 10 = fully confident). |
| Immediate adverse events | during procedure | Immediate adverse events: intraprocedural and early post-procedural events as per standard definitions (bleeding requiring endoscopic therapy, perforation, post-polypectomy syndrome, unplanned admission). Severity will be graded using an accepted endoscopy AE severity framework (e.g., ASGE lexicon). |
| Cost impact (exploratory) | during procedure | Cost impact (exploratory): incremental procedural cost derived from device utilization (snare tip vs Hybrid APC), number of exchanges, and additional haemostatic devices used. |
| Rate of incomplete STSC margin ablation by trainee operators (yes/no, Arm A only) | during procedure | Rate of incomplete STSC margin ablation by trainee operators (yes/no, Arm A only): proportion of Arm A cases in which the supervising endoscopist judged circumferential margin ablation to be incomplete at the conclusion of the trainee's attempt, necessitating supplementary ablation by the supervisor. |
Countries
Australia
Contacts
CONTACTKathleen Goodrick, BN
CONTACTMayan Eitan, MD
PRINCIPAL_INVESTIGATORMichael J Bourke, MBBS
WSLHD
Outcome results
None listed