1. CT Colonography vs Colonoscopy for the Detection of Advanced Neoplasia David H. Kim, M.D., Perry J. Pickhardt, M.D., Andrew J. Taylor, M.D., Winifred K. Leung, M.D., Thomas C. Winter, M.D., J. Louis Hinshaw, M.D., Deepak V. Gopal, M.D., Mark Reichelderfer, M.D., Richard H. Hsu, M.D., and Patrick R. Pfau, M.D. NEJM Oct 4, 2007 Volume 357:1403-1412

2. Background

3. Ct Colonography http://www.radiologyinfo.org/en/photocat/photos_pc.cfm?image= vcoloMovie.jpg&pg=ct_colo

4. Colorectal cancer: –A major cause of cancer-related mortality in the US (55,000 deaths/yr) –Preventable by detection and removal of its precursor: advanced colonic adenoma

5. Colonic adenoma progression Small adenomas < 5mm dysplasia Advance colonic adenomas >10mm Cancer 10 yrs Most likely Hyperplastic Usually do not progress to cancer

6. Study Objective

7. –Optical colonoscopy (OC) is currently the preferred screening and preventive strategy of CRC by AGS –CT colonography (CTC) is a non- invasive promising alternative screening method –Most trials examining CTC had failed to show comparative sensitivity/specificity to OC.

8. Methods

9. Study design: Single center, non randomize clinical trial comparing CTC vs OC screening in a 25 month period Study population: 6283 pt referred by primary care providers. 3120 CTC screening 3163 OC screening

11. Inclusion/Exclusion criteria Inclusion –Asymptomatic and average risk for colorectal CA Exclusion –Prior polyp surveillance –History of bowel disorder (IBD, polyposis syndromes, hereditary non polyposis colorectal cancer syndrome)

12. Screening Methods Pt identified with advanced neoplasm (mass/polyps > 6mm) by CTC were given the option of surveillance with CTC or removal of the polyp by OC. In the OC group, All polyps/masses found were removed, regardless of size or significance. All removed masses were evaluated for location relative to the splenic flexure, morphologic characteristics, and histology.

13. Screening Methods Lesions were divided into two categories: –Polyps Large: > 10mm Small: 6-9 mm Diminutive: 5mm or less –Invasive mass

14. Statistics A positive test was defined as detection of polyps of any size in the OC group and polyps of >6mm in the CTC group. The two tests were compared using student’s T-test and Chi square analyses

15. Results

17. Optical colonoscopy http://www.murrasaca.com/colonoscopy.htm A sessile polyp An adenomatous polyp

19. 3120 Patients were enrolled in CTC screening Routine follow-up in 5 yrs 2716 (87.1%) had negative findings 404 (12.9%) had positive findings With 394 polyps (>6mm) 158 (5.1%) chose ongoing imaging surveillance 227 adenomas 246 (7.9%) underwent OC with polypectomy With 193 polyps 123 Advanced neoplastic lesions 14 Cancers153 non-neoplastic tumors

22. More Information

23. Summary of Results Both CTC and OC had comparative diagnostic yield for both types of advance neoplasia (p= 0.81) CTC had an advantage of safety, no requirement for sedation, and detecting extra-colonic abnormalities There were larger number of polypectomies in the OC (2434) vs. in the CTC (561) while total advance neoplasias were similar in both (121/2434 vs 123/561)

24. PPV for advance neoplasia TP / TP+FP –CTC123 / 561 –OC 121 / 2434

25. Discussion

26. Study Strength Large sample size, similar baseline characteristics Relevant exclusion criteria Detailed pathological characterization of tissues in addition to imaging to establish comparative detection Could have significant clinical and economical impact on current practice of colon CA screening

27. Weakness Non blinded/non-randomized (selection bias) single Center Technical advancement may vary between centers for effective CTC screening True negatives in pts with lesions < 5mm in the CTC group is not determined

28. Clinical Practice Relevance Offers CTC as a non-invasive alternative to OC for comparative detection of colonic neoplasias Eliminates the need for a large number of unnecessary colonoscopies and polypectomies Due to variability in technical resources CTC may not yet be a potential replacement for OC in many practice settings

29. Thank you