S662 Comparison of Colonoscopy and CT Colonography for Colorectal Cancer Screening: A Systematic Review

Introduction: Colorectal cancer (CRC) ranks among the top causes of cancer-related illness and death globally. Timely detection through effective screening is vital for lowering CRC rates and enhancing survival rates. Although colonoscopy has long been considered the definitive method for CRC screening, CT colonography (CTC) has emerged as a non-invasive alternative. This systematic review sought to assess and compare the diagnostic effectiveness, patient-centered outcomes, procedural factors, and cost efficiency of colonoscopy and CTC in screening for CRC. Methods: A thorough literature search in the PubMed and PMC databases identified 16 pertinent articles, of which 7 studies were chosen according to specific inclusion criteria. These studies compared colonoscopy and CTC in populations at average risk for CRC. The primary variables extracted included sensitivity, specificity, detection thresholds for polyp size, patient preference, adverse events, bowel preparation techniques, the necessity for follow-up colonoscopy, and financial data. The QUADAS-2 tool was used to evaluate the risk of bias across 4 areas: patient selection, index test, reference standard, and flow and timing. Results: The 7 selected studies—Johnson et al. (2008), Graser et al. (2009), Pickhardt et al. (2011, 2015), Weinberg et al. (2011), Regge et al. (2014), and de Haan et al. (2011)—included sample sizes ranging from 200 to over 10,000. For lesions ≥10 mm, CTC showed high sensitivity (90%–96%) and specificity (86%–95%), comparable to colonoscopy. CTC was associated with minimal adverse events and generally well tolerated. While positive CTC findings required follow-up colonoscopy, non-cathartic prep improved patient acceptance. One study favored colonoscopy for post-op surveillance, though overall compliance appeared higher with CTC. Three studies supported CTC as a cost-effective screening option. Risk of bias was low in 5 studies; 2 had high or unclear risk due to limited data or selection bias. Conclusion: CT colonography provides diagnostic accuracy similar to colonoscopy for detecting significant colorectal neoplasms, with fewer risks and better patient tolerance. While colonoscopy remains the standard for its therapeutic use, CTC is a valid alternative, especially for those unwilling or unable to undergo colonoscopy. Further studies should assess long-term outcomes, cost-effectiveness, and adherence.