With this study, the investigators plan to review the performance of colonoscopic resection of large (> 1 cm) and flat lesions in the colon. The findings will help us define the role of colonoscopic resection of colon polyps and flat lesions and identity areas for improvement. The data will be used for continuing quality improvement and presenting our outcomes at academic meetings and publishing our results in peer reviewed journals.

Our goal is to collect data from our endoscopy reports (Endoscopy Clinic database) and electronic medical record system (Clinic Station) to complete a descriptive analysis of the 1) demographics, 2) colonoscopy resection procedure, and 3) outcome of resection - immediate and delayed complications, tumor recurrence, and cancer during follow-up 01/01/2014 - 12/31/2025.

Specific variable to be reviewed:

1. Patient Demographics: Age, Sex, Race, Height, Weight, BMI (patient privacy will be acknowledged).
2. Indications for Colonoscopy (screening, surveillance, symptoms or tertiary referral [EMR])
3. Comorbid conditions: cancer and surgical history, medical conditions.
4. Colonoscopy procedure: Quality of colon preparation (using the Boston Bowel Preparation Scale) 0 - 3 for each section of the colon (Ascending, Transverse, Descending and Total Colon), cecal intubation rate, cecal intubation and total procedure time, type of colonoscope (if CO2 was used in the procedure and techniques for colonoscope insertion, including position changes.
5. Examination findings: Number of polyps and nature of polyps removed (site, size, surface, vascular pattern); type of polyp removed (serrated and sessile (flat); optical features and histology of polyps.
6. Resection techniques: Biopsy, snare resection, endoscopic mucosal resection, endoscopic submucosal dissection etc.
7. Including Pathology report findings so that a comparison can be made of the optical features and actual pathology report.
8. Outcomes of colonoscopy: Complete or incomplete resection, local recurrence, need for surgery, etc
9. Outcome of colonoscopy: Complications (Bleeding and perforation).

Inclusion Criteria:

1. All Patients who have been referred for endoscopic resection of large polyps (>1 cm) and flat lesions.

Exclusion Criteria:

N/A

Patients undergoing endoscopy at MD Anderson Cancer Center in Houston, Texas