A-Quarter-Century Experience of Screening Colonoscopy

Abstract

Purpose: More than 25 years ago, we established colorectal cancer screening program using screening colonoscopy (SCS). The purpose of this study is to clarify detection rates of colorectal cancer (CRC) at first-time screening and intervals to detect CRC after negative screening. Methods: During a period between 1983 and 2008, 34,371 asymptomatic, average-risk individuals (male; 24,579, female; 9792, mean age at first-time screening; 48.7) were enrolled in the colorectal cancer screening program. Participation to first-time and repeated screening was voluntary. SCS was performed with skinny-caliber scopes (Olympus PCF) and sedation was applied only when indicated. Therapeutic interventions were performed, if clinically indicated. Totally, 125,006 screening colonoscopies were performed during this period. Records were reviewed to determine detection rates of CRC at initial and repeated colonoscopy, and intervals after negative colonoscopy to detect CRC at repeated colonoscopy. Results: Full colonoscopy to the cecum was successful in 123,529 (98.9%). At first-time SCS, CRC was detected in 241 cases (0.70%); 140 (0.41%) were limited in the mucosa and 101 (0.29%) were invasive. After negative SCS, 73 CRC were detected at repeated screening; 55 were limited in the mucosa and 18 were invasive. The intervals between negative screening and detection among these 18 invasive CRC were less than 1 year in 3 cases, 1-2 years in 5 cases, 2-3 years in 6 cases, 3-4 years in 2 cases, 4-5 years in 1 case, and over 10 years in 1 case. Conclusion: SCS using skinny-caliber scopes without sedation was well tolerated in the majority. First-time SCS effectively detected curable CRC. Interval to detect CRC after negative SCS was shorter than expected. We do not agree with currently recommended 10-year interval after negative colonoscopy.