CT Colonography for Colorectal Cancer Screening and Prevention: 20-Year Programmatic Experience at a U.S. Academic Medical Center

BACKGROUND. Utilization of CT colonography (CTC) as a screening test for colorectal cancer (CRC) may increase after the start of CMS coverage in January 2025. OBJECTIVE. The purpose of this study was to report 20-year programmatic results of a large institutional screening-focused CTC program. METHODS. This retrospective study included all CTC examinations performed from April 2004 through March 2024 at a single institution that has adopted CTC standardization and quality assurance measures. Data were extracted from a contemporaneously maintained CTC database. Programmatic experience was summarized, including correlation with subsequent optical colonoscopy (OC) findings. RESULTS. A total of 11,830 patients (6528 women and 5302 men; mean age, 56.0 years) underwent 15,431 CTC examinations; 99.3% were covered by commercial insurance or third-party payers. No colonic perforations or other major complications occurred. A total of 9168 examinations in 9168 patients were performed for primary asymptomatic screening. These examinations were positive for a polyp 6 mm or larger in 15.9% (1459/9168), a polyp 10-29 mm in 5.7% (526/9168), and a mass 3 cm or larger in 0.6% (56/9168). Of 2192 CTC-detected polyps that were at least 6 mm in this group, 61.5% were sessile, 18.3% were flat, and 16.9% were pedunculated; 45.1% were right-sided. The OC referral rate in this group was 10.5% (969/9169). Of 1683 polyps 6 mm or greater that underwent OC, concordant lesions were found in 1541 (PPV = 91.6%). Per examination, the most aggressive histology detected on OC included adenocarcinoma (0.2%; 21/9168), advanced adenoma (4.0%; 367/9168), nonadvanced tubular adenoma (3.4%; 310/9168), sessile serrated lesion (0.5%; 44/9168), hyperplastic polyp (1.2%; 112/9168), and other benign pathology (0.4%; 33/9168). In the asymptomatic screening group, 0.4% and 0.3% of examinations detected a subsequently confirmed incidental extracolonic malignancy and an incidental abdominal aortic aneurysm, respectively. A total of 1589 and 72 examinations were performed for primary asymptomatic screening in 2005 and 2023 (the first and last years of complete data availability, respectively). A total of 2886 and 616 follow-up CTC examinations were performed for routine screening and polyp surveillance, respectively. CONCLUSION. The findings support CTC screening as a safe noninvasive test for CRC prevention and detection with additional extracolonic assessment, although they also highlight the examination's decreasing utilization. CLINICAL IMPACT. These 20-year programmatic results can provide benchmarks for practices seeking to start CTC screening programs.