This is a retrospective and prospective cohort study designed to evaluate the recurrence rate and identify risk factors after endoscopic resection of gastric and intestinal polyps.

BACKGROUND: Gastric and intestinal polyps are common digestive diseases with potential for malignant transformation. Although endoscopic resection is the standard treatment, recurrence rates range from 10-50%, and the mechanisms and risk factors remain unclear.

OBJECTIVES:

Primary: To assess short-term (1-year) and long-term (3-year) recurrence rates after endoscopic polyp resection Secondary: To identify independent risk factors and develop a recurrence risk prediction model

DESIGN: Mixed retrospective-prospective cohort study

• Retrospective cohort: Patients who underwent polyp resection from 2021-2022, with follow-up data through 2024
• Prospective cohort: Patients enrolled from 2024-2025, with standardized follow-up through 2028

SETTING: Single tertiary referral center with >10,000 endoscopic polyp resections performed since 2021

PARTICIPANTS: Approximately 1,600-1,800 adult patients (≥18 years) who underwent complete endoscopic resection of gastric or intestinal polyps

FOLLOW-UP:

• Short-term: 1 year post-resection (±2 months)
• Long-term: 3 years post-resection (±3 months)

MAIN OUTCOME: Recurrence rate defined as new polyp detection at original or different sites during endoscopic surveillance

POTENTIAL RISK FACTORS: Patient demographics, polyp characteristics (size, number, location, pathology), resection method, Helicobacter pylori status, lifestyle factors, and medication use

EXPECTED IMPACT: Results will inform personalized surveillance strategies and optimize resource allocation for post-polypectomy follow-up.

Inclusion Criteria:

• Age 18 years or older
• First-time endoscopic examination (gastroscopy or colonoscopy) at the study center
• Pathologically confirmed polyp of any type (adenomatous, hyperplastic, inflammatory, fundic gland polyp, hamartomatous, serrated lesion)
• Complete endoscopic resection performed (including EMR, ESD, snare polypectomy, hot biopsy forceps, or argon plasma coagulation)
• Negative resection margins or complete resection assessed by pathology
• At least one follow-up endoscopic examination completed (for retrospective cohort) or willingness to complete follow-up (for prospective cohort)
• Complete baseline clinical data available

Exclusion Criteria:

• Hereditary polyposis syndromes (familial adenomatous polyposis, Lynch syndrome, Peutz-Jeghers syndrome, juvenile polyposis syndrome)
• Inflammatory bowel disease (ulcerative colitis or Crohn's disease)
• Previous history of gastric or colorectal cancer
• Cancer detected at initial resection (stage T1b or higher)
• Non-polyp pathology (e.g., submucosal tumors, normal mucosa)
• Incomplete resection with positive margins that were not re-treated
• Lost to follow-up with no available surveillance data (for retrospective cohort)
• Pregnancy at time of enrollment
• Inability or unwillingness to provide informed consent (for prospective cohort)

The study population consists of adult patients (≥18 years) who underwent complete endoscopic resection of gastric or intestinal polyps at our tertiary referral center. This includes two cohorts: (1) Retrospective cohort: patients treated from 2021-2022 with existing follow-up data; (2) Prospective cohort: newly enrolled patients from 2024-2025. Eligible participants must have pathologically confirmed polyps (adenomatous, hyperplastic, inflammatory, fundic gland, serrated, or hamartomatous) with negative resection margins. The population represents a diverse group with varying polyp characteristics (size range: <5mm to >20mm; single or multiple polyps; gastric or colorectal locations) and different resection methods (EMR, ESD, snare polypectomy). Excluded are patients with hereditary polyposis syndromes, inflammatory bowel disease, prior gastrointestinal malignancy, or cancer detected at initial resection.