We will conduct a multicenter, parallel-group, non-inferiority RCT in persons with IBD undergoing colorectal neoplasia screening with high-definition white light colonoscopy, comparing a strategy of sampling visible lesions alone to a conventional strategy of sampling both visible lesions as well as normal-appearing mucosa using non-targeted biopsies. The primary outcome is the neoplasia detection rate. The required sample size to demonstrate non-inferiority is 1952 persons.

Inclusion Criteria:

• Each potential participant must satisfy all of the following criteria to be enrolled in the study.

  • ≥ 18 years old

  • Historical endoscopic/histologic disease extending beyond the rectum in UC or involving ≥ 1/3 of colorectum in CD> 50% of colon present, with remaining colon meeting above minimum criteria for disease extent (beyond rectum in UC, ≥1/3 colorectum in CD)

  • cIBD ≥ 8 years duration (or at any time after diagnosis if a patient also has primary sclerosing cholangitis)

  • In symptomatic remission at time of colonoscopy

    • For CD: Harvey-Bradshaw Index < 541
    • For UC or IBDU: Partial Mayo Score ≤ 242

  • Major purpose of colonoscopy is neoplasia screening/surveillance

  • Undergoing colonoscopy with high-definition white light endoscopy

Exclusion Criteria:

• Persons who are unable to provide informed consent
• Persons with a history of colorectal cancer
• Persons with prior subtotal or total colectomy (>50% of colon removed)
• Persons undergoing repeat colonoscopy to follow-up on recently diagnosed neoplasia identified within the past year
• Persons undergoing pancolonic chromoendoscopy or pancolonic virtual chromoendoscopy
• Colon mucosa visibility deemed inadequate for surveillance after washing/suctioning (Boston Bowel Preparation Score of 0 or 1 in any segment)
• Incomplete colonoscopy (unable to reach cecum or terminal ileum [if no cecum])
• Moderate-to-severe inflammation (Mayo 2-3) involving ≥ 25% of colorectum or mild inflammation (Mayo 1) involving ≥ 50% of colorectum