title: Prediction of synchronous colorectal cancers by computed tomography in subjects receiving an incomplete colonoscopy: a single-center study.
abstract: OBJECTIVE
  To assess the value of computed tomography (CT) for diagnosis of synchronous colorectal cancers (SCRCs) involving incomplete colonoscopy.
  
  
  METHODS
  A total of 2123 cases of colorectal cancer (CRC) were reviewed and divided into two groups according to whether a complete or incomplete colonoscopy was performed. CT results and final histological findings were compared to calculate the sensitivity and specificity associated with CT for detection of SCRCs following complete vs incomplete colonoscopy. Factors affecting the CT detection were also analyzed.
  
  
  RESULTS
  Three hundred and seventy-four CRC patients underwent incomplete colonoscopy and 1749 received complete colonoscopy. Fifty-six cases of SCRCs were identified by CT, and 36 were missed. In the incomplete colonoscopy group, the sensitivity and specificity of CT were 44.8% and 93.6%, respectively. The positive and negative predictive values were 23.6% and 95.0%, respectively. In contrast, the sensitivity and specificity of CT for the complete colonoscopy group were 68.3% and 97.0%, while the positive and negative predictive values were 22.2% and 98.7%, respectively. In both groups, the mean maximum dimension of the concurrent cancers identified in the CT-negative cases was shorter than in the CT-positive cases (incomplete group: P = 0.02; complete group: P < 0.01) Topographical proximity to synchronous cancers was identified as a risk factor for missed diagnosis (P = 0.03).
  
  
  CONCLUSIONS
  CT has limited sensitivity in detecting SCRCs in patients receiving incomplete colonoscopy. Patients with risk factors and negative CT results should be closely examined and monitored.
authors: Er-Jun Pang, Wei-Jie Liu, Jia-Yuan Peng, Department of Surgery, the Sixth People's Hospital Affiliated to Shanghai Jiao Tong University, Shanghai 200233, China.
authors: Er-Jun
authors: EJ
authors: Pang
authors: Er-Jun Pang, Wei-Jie Liu, Jia-Yuan Peng, Department of Surgery, the Sixth People's Hospital Affiliated to Shanghai Jiao Tong University, Shanghai 200233, China.
authors: Wei-Jie
authors: WJ
authors: Liu
authors: Er-Jun Pang, Wei-Jie Liu, Jia-Yuan Peng, Department of Surgery, the Sixth People's Hospital Affiliated to Shanghai Jiao Tong University, Shanghai 200233, China.
authors: Jia-Yuan
authors: JY
authors: Peng
authors: Er-Jun Pang, Wei-Jie Liu, Jia-Yuan Peng, Department of Surgery, the Sixth People's Hospital Affiliated to Shanghai Jiao Tong University, Shanghai 200233, China.
authors: Ni-Wei
authors: NW
authors: Chen
authors: Er-Jun Pang, Wei-Jie Liu, Jia-Yuan Peng, Department of Surgery, the Sixth People's Hospital Affiliated to Shanghai Jiao Tong University, Shanghai 200233, China.
authors: Jian-Hong
authors: JH
authors: Deng
mesh_terms: D000230:Adenocarcinoma / Q000000981:diagnostic imaging* / Q000473:pathology*; D000368:Aged; D002681:China; D003113:Colonoscopy; D015179:Colorectal Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology*; D005188:False Negative Reactions; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009378:Neoplasms, Multiple Primary / Q000000981:diagnostic imaging* / Q000473:pathology*; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed
keywords: Colonoscopy; Computed tomography; Synchronous colorectal cancer