With this study, we plan to review the performance of colonoscopy in colon cancer screening and surveillance, especially with the recent improvements in endoscopic technology (high definition endoscopes), use of split dose preparation which provides excellent colon preparation for detection of lesions and increasing awareness and detection of flat lesions of the colon. The findings will help us define the role of colonoscopy screening 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.

Investigator's goal is to collect data from the endoscopy reports and clinic station reports to complete a descriptive analysis of the demographics, colonoscopy procedure performance, and assess the type of benign colon polyps detected during screening and surveillance from 02/01/2000 - 12/31/2020.

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 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: adenoma detections (tubular and villous), cancer and quality metrics.
9. Outcome of colonoscopy: Complications (Bleeding and performance).

Inclusion Criteria:

1. All Patients who have undergone colonoscopy for screening, surveillance or symptom evaluation.

Exclusion Criteria:

1. None

Chart review from participants receiving colonoscopy at UT MD Anderson Cancer Center in Houston, Texas from 02/01/2009 - 12/31/2020.