This multicenter, prospective, randomized non inferiority trial, conducted at four Israeli hospitals, will evaluate whether a relaxed surveillance strategy after piecemeal endoscopic mucosal resection (pEMR) of large non pedunculated colorectal polyps (LNPCPs, ≥20 mm) is as safe and effective as the current standard intensive surveillance. Approximately 760 adults undergoing complete pEMR with margin ablation will be randomized 1:1 into:

Standard Surveillance: Colonoscopy at 6, 18, and 48 months

Relaxed Surveillance: Colonoscopy at 12 and 48 months

All colonoscopies will be performed using high definition white light and narrow band imaging, with biopsies obtained only if recurrence is suspected. The investigators hypothesize that a relaxed surveillance strategy will be non inferior to the current standard intensive surveillance. If non inferiority is demonstrated, the study may support guideline changes toward reduced surveillance frequency after pEMR with margin ablation, potentially decreasing patient burden and healthcare costs.

Inclusion Criteria:

• Adults aged 18 years and older
• Undergoing pEMR of LNPCPs
• Able to provide informed consent and comply with follow-up requirements

Exclusion Criteria:

• Patients with invasive cancer identified during the index procedure
• en bloc resection
• Patients unable to attend follow-up colonoscopies due to comorbid conditions
• Patients who require additional surgery for polyp removal or other complications