Michael E. Zalis, MD; Michael A. Blake, MB BCh; Wenli Cai, PhD; Peter F. Hahn, MD, PhD; Elkan F. Halpern, PhD; Imrana G. Kazam, PhD; Myles Keroack, MD; Cordula Magee, PhD; Janne J. Näppi, PhD; Rocio Perez-Johnston, MD; John R. Saltzman, MD; Abhinav Vij, MD; Judy Yee, MD; Hiroyuki Yoshida, PhD
Disclaimer: Drs. Zalis, Cai, Näppi, and Yoshida are co-inventors of electronic cleansing and computer-aided detection software patents assigned to their home institution, without associated royalties.
Acknowledgment: The authors thank the clinical staff of the departments of gastroenterology, radiology, and pathology of the participating institutions for the excellent care provided during the performance of this study.
Grant Support: Dr. Zalis is supported by GE Healthcare (03-OPQ-001), the American Cancer Society (RSG-08-221-01-CCE), and the National Institutes of Health (1K22CA098422). Drs. Zalis, Cai, Näppi, and Yoshida are supported by the National Institutes of Health (1 RO1 CA095279). Dr. Yoshida is supported by the American Cancer Society (RSG-05-088-01-CCE).
Potential Conflicts of Interest: Disclosures can be viewed at www.acponline.org/authors/icmje/ConflictOfInterestForms.do?msNum=M11-2437.
Reproducible Research Statement:Study protocol, statistical code, and data set: Not available.
Requests for Single Reprints: Michael E. Zalis, MD, Department of Imaging, Massachusetts General Hospital, Suite 400A, 25 New Chardon Street, Boston, MA 02114; e-mail, mailto:firstname.lastname@example.org.
Current Author Addresses: Drs. Zalis, Blake, Cai, Hahn, Kazam, Magee, Näppi, Perez-Johnston, Vij, and Yoshida: Department of Imaging, Massachusetts General Hospital, Suite 400A, 25 New Chardon Street, Boston, MA 02114.
Dr. Halpern: Institute for Technology Assessment, 101 Merrimac Street, Boston, MA 02114.
Dr. Keroack: Eau Claire Center, 2116 Craig Road, Eau Claire, WI 54701.
Dr. Saltzman: Brigham and Women's Hospital, 75 Francis Street, Boston, MA 02115.
Dr. Yee: Radiology and Biomedical Imaging, University of California, San Francisco, and Department of Radiology, San Francisco Veterans Affairs Medical Center, 4150 Clement Street, San Francisco, CA 94121.
Author Contributions: Conception and design: M.E. Zalis, W. Cai, E.F. Halpern, M. Keroack.
Analysis and interpretation of the data: M.A. Blake, P.F. Hahn, E.F. Halpern, I.G. Kazam, R. Perez-Johnston, A. Vij, J. Yee.
Drafting of the article: M.E. Zalis, M.A. Blake, P.F. Hahn.
Critical revision of the article for important intellectual content: M.E. Zalis, M.A. Blake, P.F. Hahn, J.J. Näppi, J.R. Saltzman, J. Yee, H. Yoshida.
Final approval of the article: M.E. Zalis, M.A. Blake, W. Cai, P.F. Hahn, E.F. Halpern, M. Keroack, J.R. Saltzman, J. Yee.
Provision of study materials or patients: M.E. Zalis, E.F. Halpern, I.G. Kazam, M. Keroack, J.R. Saltzman, J. Yee, H. Yoshida.
Statistical expertise: E.F. Halpern, A. Vij.
Obtaining of funding: M.E. Zalis, H. Yoshida.
Administrative, technical, or logistic support: M.E. Zalis, W. Cai, I.G. Kazam, M. Keroack, C. Magee, J.J. Näppi, J.R. Saltzman, H. Yoshida.
Collection and assembly of data: M.E. Zalis, P.F. Hahn, I.G. Kazam, M. Keroack, C. Magee, J.J. Näppi, J.R. Saltzman, A. Vij, J. Yee, H. Yoshida.
Colon screening by optical colonoscopy (OC) or computed tomographic colonography (CTC) requires a laxative bowel preparation, which inhibits screening participation.
To assess the performance of detecting adenomas 6 mm or larger and patient experience of laxative-free, computer-aided CTC.
Prospective test comparison of laxative-free CTC and OC. The CTC included electronic cleansing and computer-aided detection. Optical colonoscopy examinations were initially blinded to CTC results, which were subsequently revealed during colonoscope withdrawal; this method permitted reexamination to resolve discrepant findings. Unblinded OC served as a reference standard. (ClinicalTrials.gov registration number: NCT01200303)
Multicenter ambulatory imaging and endoscopy centers.
605 adults aged 50 to 85 years at average to moderate risk for colon cancer.
Per-patient sensitivity and specificity of CTC and first-pass OC for detecting adenomas at thresholds of 10 mm or greater, 8 mm or greater, and 6 mm or greater; per-lesion sensitivity and survey data describing patient experience with preparations and examinations.
For adenomas 10 mm or larger, per-patient sensitivity of CTC was 0.91 (95% CI, 0.71 to 0.99) and specificity was 0.85 (CI, 0.82 to 0.88); sensitivity of OC was 0.95 (CI, 0.77 to 1.00) and specificity was 0.89 (CI, 0.86 to 0.91). Sensitivity of CTC was 0.70 (CI, 0.53 to 0.83) for adenomas 8 mm or larger and 0.59 (CI, 0.47 to 0.70) for those 6 mm or larger; sensitivity of OC for adenomas 8 mm or larger was 0.88 (CI, 0.73 to 0.96) and 0.76 (CI, 0.64 to 0.85) for those 6 mm or larger. The specificity of OC at the threshold of 8 mm or larger was 0.91 and at 6 mm or larger was 0.94. Specificity for OC was greater than that for CTC, which was 0.86 at the threshold of 8 mm or larger and 0.88 at 6 mm or larger (P = 0.02). Reported participant experience for comfort and difficulty of examination preparation was better with CTC than OC.
There were 3 CTC readers. The survey instrument was not independently validated.
Computed tomographic colonography was accurate in detecting adenomas 10 mm or larger but less so for smaller lesions. Patient experience was better with laxative-free CTC. These results suggest a possible role for laxative-free CTC as an alternate screening method.
GE Healthcare and the American Cancer Society.
Zalis ME, Blake MA, Cai W, Hahn PF, Halpern EF, Kazam IG, et al. Diagnostic Accuracy of Laxative-Free Computed Tomographic Colonography for Detection of Adenomatous Polyps in Asymptomatic Adults: A Prospective Evaluation. Ann Intern Med. 2012;156:692–702. doi: 10.7326/0003-4819-156-10-201205150-00005
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Published: Ann Intern Med. 2012;156(10):692-702.
Cancer Screening/Prevention, Colonoscopy/Sigmoidoscopy, Colorectal Cancer, Gastroenterology/Hepatology, Hematology/Oncology.
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