Chromocolonoscopy with acetic acid and indigo carmine has shown promise for improving the detection of sessile serrated lesions (SSLs), the precursor lesions responsible for a substantial proportion of interval colorectal cancers. Previous studies have demonstrated its potential to enhance visualization of both adenomatous and non-adenomatous polyps, particularly the subtle SSLs that are frequently missed during conventional white-light colonoscopy. However, high-quality randomized controlled trials comparing chromocolonoscopy with standard white-light imaging to provide definitive evidence on its efficacy for SSL detection are lacking. We therefore conducted a multicenter, prospective, randomized controlled trial to evaluate the diagnostic yield of acetic acid-indigo carmine chromocolonoscopy versus standard colonoscopy for SSL detection.

Inclusion Criteria:

• Patients whose age are between 45-85
• Patients who have indications for screening
• Patients who have signed inform consent form.

Exclusion Criteria:

• Patients undergoing surveillance colonoscopy after polypectomy or therapeutic colonoscopy for known polyps
• Patients with a history of colonoscopy within the past 5 years
• Patients with highly suspected or confirmed colorectal cancer
• Patients with alarming signs or symptoms: hematochezia, melena, unexplained anemia, weight loss, abdominal mass, positive digital rectal examination
• Pregnant or breastfeeding women
• Patients with gastrointestinal obstruction
• Patients with inflammatory bowel disease, colonic polyposis, or melanosis coli
• Patients with coagulation disorders or who have taken antiplatelets or anticoagulants (e.g., aspirin, warfarin) within 7 days before colonoscopy
• Patients currently participating in another clinical trial or who have participated in another clinical trial within the preceding 60 days
• Patients with failed cecal intubation for any reason (e.g., obstructing lesion, intolerance of the procedure)
• Patients with an Aronchick bowel preparation score >3 at colonoscope insertion, indicating inadequate preparation requiring a repeat bowel preparation
• Patients who have used bowel preparation agents not recommended by guidelines, such as oral sodium phosphate or senna
• Patients with known allergy to acetic acid-indigo carmine, brilliant blue dye, or medications related to colonoscopy
• Patients with missing essential information in the case report form prior to enrollment