Colonoscopy Outcomes in Average-Risk Screening Equivalent Young Adults: Data From the New Hampshire Colonoscopy Registry.

INTRODUCTION: Data are needed to further inform the American Cancer Society recommendation to begin colorectal cancer (CRC) screening at age 45. We used the New Hampshire Colonoscopy Registry to compare the prevalence of advanced neoplasia (AN) in an "average-risk screening equivalent" group aged 45-49 years with patients aged 50-54 years and older receiving screening colonoscopy. METHODS: Colonoscopies in adults older than 50 years of age usually have diagnostic indications of varying clinical significance. We combined patients older than 50 years with diagnostic indications (abdominal pain and constipation) expected to yield AN prevalence similar to screening low AN risk and those with a screening indication to form an "average-risk screening equivalent" group. We excluded high-risk indications (e.g., bleeding and anemia), surveillance examinations, and patients with a first-degree family history of CRC, incomplete examinations, and poor bowel preparation. We calculated prevalence/adjusted risks for AN (≥1 cm, villous, high-grade dysplasia, and CRC) and clinically significant serrated polyps (large [≥1 cm] hyperplastic polyps, sessile serrated polyp, traditional serrated adenomas, and proximal hyperplastic polyp ≥ 5 mm). RESULTS: In our sample (n = 40,812), AN prevalence was as follows: <40 years (1.1%), 40-44 years (3.0%), 45-49 years (3.7%), 50-54 years (3.6%), 55-59 years (5.1%), and 60+ years (6.7%) (P < 0.0001 across all groups). The prevalence of both AN and clinically significant serrated polyp was similar in the 45-49 and 50-54 years' age groups. Furthermore, the prevalence of AN increased significantly in the 40-44 group as compared to that in the <40 years group. Adjusted analyses confirmed these results. The diagnostic indications considered to have low risk were not predictive of AN. DISCUSSION: New Hampshire Colonoscopy Registry data, demonstrating an increase in AN risk starting at age 40 and a similar prevalence for individuals aged 45-49 and those ages 50-54, provide clinically useful evidence for optimization of prevention and the age to start screening. However, this is a complex issue involving additional considerations that will need to be addressed.