title: Diagnostic performance of contrast enhanced CT and 18F-FDG PET/CT in suspicious recurrence of biliary tract cancer after curative resection.
abstract: BACKGROUND
  Because of the late clinical presentation of biliary tract cancer (BTC), only 10% of patients are eligible for curative surgery. Even among those patients who have undergone curative surgery, most patients develop recurrent cancer. This study is to determine the clinical role of 18F-FDG PET/CT during post-operative surveillance of suspected recurrent BTC based on symptoms, laboratory findings and contrast-enhanced CT (ceCT) findings.
  
  
  METHODS
  We consecutively enrolled 50 patients with BTC who underwent curative surgery. An 18F-FDG PET/CT was obtained for assessment of recurrence based on clinical suspicion during post-operative surveillance. The final confirmation of recurrence was determined pathologically or clinically. When a pathologic confirmation was impossible or inconclusive, a clinical confirmation was used by radiologic correlation with subsequent follow-up ceCT at a minimum of 3-month intervals. Diagnostic efficacy was evaluated by comparing the results of ceCT and 18F-FDG PET/CT with the final diagnosis.
  
  
  RESULTS
  Among the 50 patients, 34(68%) were confirmed to have a recurrence. PET/CT showed higher sensitivity (88% vs. 76%, p=0.16) and accuracy (82% vs. 66%, p=0.11) for recurrence compared to ceCT, even though the difference was not significant. The positive (86% vs. 74%, p=0.72) and negative predictive values for recurrence (73% vs. 47%, p=0.55) were not significantly different between PET/CT and ceCT. However, an additional PET/CT on ceCT significantly improved the sensitivity than did a ceCT alone (94% [32/34] for PET/CT on ceCT vs. 76% [26/34] for ceCT alone, p=0.03) without increasing the specificity, positive predictive value, and negative predictive value.
  
  
  CONCLUSIONS
  18F-FDG PET/CT alone is not more sensitive or specific than ceCT in the detection of recurrent BTC after curative surgery. These results do not reach statistical significance, probably due to the low number of patients. However, an additional 18F-FDG PET/CT on ceCT significantly improves the sensitivity of detecting recurrences.
authors: Department of Internal Medicine, Seoul National University Hospital, and Cancer Research Institute, Department of Molecular Medicine & Biopharmaceutical Sciences, Graduate School of Convergence, Seoul National University College of Medicine, Seoul, Republic of Korea.
authors: Yun-Gyoo
authors: YG
authors: Lee
authors: Sae-Won
authors: SW
authors: Han
authors: Do-Youn
authors: DY
authors: Oh
authors: Eui Kyu
authors: EK
authors: Chie
authors: Jin-Young
authors: JY
authors: Jang
authors: Seock-Ah
authors: SA
authors: Im
authors: Tae-You
authors: TY
authors: Kim
authors: Sun-Whe
authors: SW
authors: Kim
authors: Sung Whan
authors: SW
authors: Ha
authors: Yung-Jue
authors: YJ
authors: Bang
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