Incidence of Precancerous Lesions Among Patients Aged 40 to 45 Years Who Underwent Screening Colonoscopy

Background: Colorectal cancer (CRC) is the third most common cancer worldwide and ranks second among cancer-related deaths in the United Arab Emirates. While most international guidelines recommend CRC screening beginning at age 50 or 45, the Abu Dhabi Public Health Centre recommends screening from age 40. However, the yield of screening colonoscopy in individuals aged 40-45 remains unclear. Objective: To determine the prevalence of precancerous adenomas and colorectal cancer in average-risk patients aged 40-45 in the UAE population. Methods: This retrospective cohort study analyzed data from all average-risk patients aged 40-45 who underwent screening colonoscopy between 2019 and 2024. Of 627 patients, 432 (68.9%) were referred via GI clinic visits, 130 (20.7%) from family medicine, and 65 (10.4%) were self-referrals. Data on colonoscopy findings, specifically the detection of adenomas, advanced neoplasms, and colorectal cancer were collected. Both non-modifiable risk factors (age, gender) and modifiable risk factors (smoking, BMI, alcohol consumption) were assessed. Results: A total of 627 average-risk adults underwent screening colonoscopy. Adenomas were detected in 123 patients (19.6%), including 3 (0.5%) with serrated lesions, 4 (0.6%) with polyps ≥10 mm, 1 (0.2%) with high-grade dysplasia, and 5 (0.8%) meeting criteria for advanced lesions. Two patients (0.3%) were diagnosed with colorectal cancer. Smoking was the only independent predictor of adenoma presence (OR 1.86; 95% CI 1.08–3.22; p = 0.026). The number needed to scope to detect one adenoma was 5.1 colonoscopies. Conclusion: Screening colonoscopy revealed a clinically significant burden of precancerous lesions and identified smoking as the key modifiable risk factor, supporting consideration of starting colorectal cancer screening before age 45 in the UAE.