Is Adenoma Detection Rate Still the Quality Indicator for Screening Colonoscopy in Younger Patients?

Abstract

Introduction: Recent guidelines from the American Cancer Society (ACS) recommend to start colon cancer screening at 45 years in average-risk patient population. Previously, it has been established that patients with family history (FH) of colorectal cancer (CRC) at any age should undergo screening at age 40 years. Despite these guidelines, data on the prevalence of adenomas in these patients is scant. We aimed to examine and compare the prevalence of adenomas in 40 to 49-year-old individuals undergoing colonoscopy because of FH of CRC of a first-degree relative (FDR) with CRC versus patients without any family history of CRC. Methods: A retrospective cross sectional study was performed using our electronic endoscopy database. Study subjects (cases) included all 40-49-year-old patients undergoing their index colonoscopy for diagnostic purposes (abdominal pain, diarrhea, weight loss, altered bowel habits, etc) at our center from January 2010 to September 2017. The control group consisted of all 40-49-year-old patients undergoing their index screening colonoscopy for a FDR with CRC. Exclusion criteria included patients who underwent colonoscopy for overt gastrointestinal bleeding, inflammatory bowel disease, patients who had previous colonoscopies, a history of familial adenomatous polyposis, hereditary non polyposis CRC. Results: A total of 2059 patients were included in the study. Mean age of these patients was 44.7 years, and 59.8% were males. Number of patients in the control group were 355, and number in study group was 1704. The adenoma detection rate (ADR) was 27.8% in the control group, and 19.7% (p=0.001) in the study group. The rate of neoplasia detected was 2.2% in patients with FH of CRC, and 1.3% in patients without FH of CRC (p=0.18). Conclusion: The ADR in average-risk 40-49 year old patients is less than the current recommended ADR in patients with average risk undergoing their screening colonoscopy at 50 years of age (i.e. 25%). However, the rate of neoplasia detected was comparable. This suggests that although early colonoscopy is beneficial in detecting CRC, but further studies are needed to look for factors beyond the traditional adenoma-carcinoma pathway in younger individuals. With the advent of the latest ACS guidelines, new quality benchmark for ADR will need to be established in average risk patients younger than 50 years of age undergoing screening colonoscopy. Future large multi-center prospective studies are needed to confirm this finding.225_A Figure 1 No Caption available.225_B Figure 2 No Caption available.