S0337 Increased Risk of Left-Sided Advanced Colorectal Neoplasia but Not Serrated Polyps in Adults Less Than 50 Years Who Present With Bleeding: Data From the New Hampshire Colonoscopy Registry

Abstract

INTRODUCTION: Data regarding advanced neoplasia and serrated polyps (SPs) in adults <50 years of age who present with bleeding are vital for screening and diagnosing CRC in adults <50. We used data from the New Hampshire Colonoscopy Registry (NHCR) to compare the anatomical location of advanced neoplasia and SPs in average risk patients to those who present with bleeding. METHODS: An average risk screening equivalent cohort was created for the analysis. Since many adults <50 have diagnostic exams, we formed an “average risk” sample by selecting diagnostic exams with indications that are associated with a low risk for advanced neoplasia such as change in bowel habits (e.g., constipation) and abdominal pain (Cha et al GIE 2015) and combining these with screening exams. We excluded higher risk indications from this cohort (e.g., anemia or bleeding) as well as surveillance, family history of first degree relative with CRC, IBD, incomplete exams, and poor bowel prep. We compared outcomes for the average risk equivalent group to our group of interest, i.e., exams with bleeding indications. Outcomes were advanced neoplasia (adenomas >1 cm, with villous elements, HGD, and CRC) and clinically important SPs ((HP > 1 cm), any sessile serrated polyp and traditional serrated adenomas) as stratified by anatomical location, left sided (distal to splenic flexure) and right sided (proximal to descending colon). We present absolute and adjusted risks for advanced neoplasia and SPs. Covariates were age, sex, smoking and BMI. RESULTS: There were 5855 NHCR average risk patients <50 years (avg age 38.5 yrs) and 2814 with bleeding (37.6 yrs). The absolute and adjusted risks for left sided advanced neoplasia were significantly higher for patients with bleeding than those in the average risk equivalent group (OR = 1.73 95% CI: 1.28–2.34) (Table 1). The increased risk was especially high for left sided CRC (OR = 4.82 95% CI 1.47–15.81). Conversely there was no increased risk for right sided advanced neoplasia, CRC or proximal or distal SPs. CONCLUSION: Young patients with bleeding had an increased risk for left sided advanced neoplasia. These data support current recommendations that patients <50 with bleeding should undergo evaluation for colorectal neoplasia, especially of the left side of the colon. However, there was no increased risk for SPs or right sided neoplasia or CRC in young individuals with bleeding, highlighting a clinically relevant difference in outcomes that may affect choice of testing options for this group.Table 1.: As compared to the average risk screening equivalent group, there was an increased risk for left sided neoplasia including CRC but not for right sided neoplasia or serrated polyps at any location