Nagata K, Endo S, Honda T, Yasuda T, Hirayama M, Takahashi S, Kato T, Horita S, Furuya K, Kasai K, Matsumoto H, Kimura Y, Utano K, Sugimoto H, Kato H, Yamada R, Yamamichi J, Shimamoto T, Ryu Y, Matsui O, Kondo H, Doi A, Abe T, Yamano HO, Takeuchi K, Hanai H, Saida Y, Fukuda K, Näppi J, and Yoshida H
Objectives: The objective of this study was to assess prospectively the diagnostic accuracy of computer-assisted computed tomographic colonography (CTC) in the detection of polypoid (pedunculated or sessile) and nonpolypoid neoplasms and compare the accuracy between gastroenterologists and radiologists., Methods: This nationwide multicenter prospective controlled trial recruited 1,257 participants with average or high risk of colorectal cancer at 14 Japanese institutions. Participants had CTC and colonoscopy on the same day. CTC images were interpreted independently by trained gastroenterologists and radiologists. The main outcome was the accuracy of CTC in the detection of neoplasms ≥6 mm in diameter, with colonoscopy results as the reference standard. Detection sensitivities of polypoid vs. nonpolypoid lesions were also evaluated., Results: Of the 1,257 participants, 1,177 were included in the final analysis: 42 (3.6%) were at average risk of colorectal cancer, 456 (38.7%) were at elevated risk, and 679 (57.7%) had recent positive immunochemical fecal occult blood tests. The overall per-participant sensitivity, specificity, and positive and negative predictive values for neoplasms ≥6 mm in diameter were 0.90, 0.93, 0.83, and 0.96, respectively, among gastroenterologists and 0.86, 0.90, 0.76, and 0.95 among radiologists (P<0.05 for gastroenterologists vs. radiologists). The sensitivity and specificity for neoplasms ≥10 mm in diameter were 0.93 and 0.99 among gastroenterologists and 0.91 and 0.98 among radiologists (not significant for gastroenterologists vs. radiologists). The CTC interpretation time by radiologists was shorter than that by gastroenterologists (9.97 vs. 15.8 min, P<0.05). Sensitivities for pedunculated and sessile lesions exceeded those for flat elevated lesions ≥10 mm in diameter in both groups (gastroenterologists 0.95, 0.92, and 0.68; radiologists: 0.94, 0.87, and 0.61; P<0.05 for polypoid vs. nonpolypoid), although not significant (P>0.05) for gastroenterologists vs. radiologists., Conclusions: CTC interpretation by gastroenterologists and radiologists was accurate for detection of polypoid neoplasms, but less so for nonpolypoid neoplasms. Gastroenterologists had a higher accuracy in the detection of neoplasms ≥6 mm than did radiologists, although their interpretation time was longer than that of radiologists., Competing Interests: Guarantors of the article: Hiroyuki Yoshida, PhD, and Koichi Nagata, MD, PhD. Specific author contributions: Acquisition of data: Honda, Yasuda, Hirayama, Takahashi, Kato, Horita, Furuya, Kasai, Matsumoto, Kimura, Kato, Kondo, Abe, Yamano, Takeuchi, Saida, and Fukuda; analysis and interpretation of data: Nagata, Honda, Hirayama, Kato, Furuya, Matsumoto, Utano, Ryu, and Kasai; drafting of the manuscript: Nagata and Yoshida; critical revision of the manuscript for important intellectual content: all authors; statistical analysis: Yamamichi and Shimamoto; obtaining funding: Nagata and Yoshida; administrative, technical, or material support: Yoshida, Nagata, Endo, Näppi, Sugimoto, Yamada, Matsui, Doi, Yamano, Hanai, and Saida; study supervision: Yoshida and Nagata. All authors had access to the study data and reviewed and approved the final manuscript. Financial support: This study was in part supported by the Japanese CTC Society, Ajinomoto Pharmaceutical, and R01CA095279 (Principal Investigator: Yoshida) from the National Institutes of Health, Bethesda, Maryland. The Japanese CTC Society did have a role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript, and decision to submit the manuscript for publication. The industry sponsor, Ajinomoto Pharmaceutical, had no role in the above aspects of the study. The National Institutes of Health had no role in the above aspects of the study, but had a role in supporting the development of computer-aided diagnosis software for image interpretation used in the study through grant R01CA095279. Potential competing interests: Koichi Nagata reported that he is an inventor of PEG-C bowel preparation and holds a licensing agreement with Ajinomoto Pharmaceutical, without associated royalty, had a 1-year consulting agreement with Aze, during 2010–2011 with associated compensation, and was partially supported by the National Institutes of Health. Janne Näppi reported that he is a co-inventor of CAD software patents assigned to his home institution, without associated royalties, and was partially supported by the National Institutes of Health. Hiroyuki Yoshida reported that he is a co-inventor of CAD software patents assigned to his home institution, without associated royalties, had a 1-year consulting agreement with Aze, during 2010–2011 with associated compensation, and was partially supported by the National Institutes of Health. The remaining authors declare no conflict of interest.