To evaluate the adenoma detection rate (ADR) in patients under 50 years of age undergoing colonoscopy and to characterize the features of adenomas/polyps in this population.

A retrospective analysis was conducted of colonoscopy procedures performed between 2022-2023 in patients under 50 years of age at a district general hospital in the UK. Data collected included patient demographics, procedure indications, colonoscopy findings, and histopathological results. Adenoma and polyp characteristics including location, histological type, and grade of dysplasia were recorded and analyzed.

A total of 3800 colonoscopies were carried out during this time. 234 colonoscopies performed in patients under 50 years of age. Patients with inflammatory bowel disease and polyposis syndrome were excluded.

Overall adenoma detection rate was 14.96% (35/234). The mean age of patients with adenomas was 38.12 years (range 33-49) with a 22:13 M: F of 1.7:1. One patient was found to have an adenocarcinoma.

Common indications for colonoscopy included: rectal bleeding (15/35, 42.9%), altered bowel habits (13/35, 37.1%), abdominal pain (9/35, 25.7%), and anaemia (7/35, 20%).

Overall serrated polyp detection rate was 4.27% (10/234).

ADR plus (defined as the proportion of patients with at least one adenoma or serrated polyp) was 18.4% (43/234).

Advanced adenomas were found in 25.7% (9/35).

Table 1: Adenoma Characteristics (n=35)

This study demonstrates a significant ADR of 15% in patients under 50 years of age undergoing colonoscopy. Adenomas were relatively evenly distributed throughout the colon, with slight left-sided predominance (45.7%). The presence of high-grade dysplasia in 8.6% of cases and one adenocarcinoma highlights the clinical significance of evaluating significant symptoms in younger patients. These findings support the value of colonoscopy in symptomatic patients under 50 and contribute to evidence informing screening strategies for younger populations.