title: Prevalence and malignancy risk of focal colorectal incidental uptake detected by (18)F-FDG-PET or PET/CT: a meta-analysis.
abstract: BACKGROUND
  The aim of the study was to meta-analyze published data about prevalence and malignancy risk of focal colorectal incidentalomas (FCIs) detected by Fluorine-18-Fluorodeoxyglucose positron emission tomography or positron emission tomography/computed tomography ((18)F-FDG-PET or PET/CT).
  
  
  METHODS
  A comprehensive computer literature search of studies published through July 31(st) 2012 regarding FCIs detected by (18)F-FDG-PET or PET/CT was performed. Pooled prevalence of patients with FCIs and risk of malignant or premalignant FCIs after colonoscopy or histopathology verification were calculated. Furthermore, separate calculations for geographic areas were performed. Finally, average standardized uptake values (SUV) in malignant, premalignant and benign FCIs were reported.
  
  
  RESULTS
  Thirty-two studies comprising 89,061 patients evaluated by (18)F-FDG-PET or PET/CT were included. The pooled prevalence of FCIs detected by (18)F-FDG-PET or PET/CT was 3.6% (95% confidence interval [95% CI]: 2.6-4.7%). Overall, 1,044 FCIs detected by (18)F-FDG-PET or PET/CT underwent colonoscopy or histopathology evaluation. Pooled risk of malignant or premalignant lesions was 68% (95% CI: 60-75%). Risk of malignant and premalignant FCIs in Asia-Oceania was lower compared to that of Europe and America. A significant overlap in average SUV was found between malignant, premalignant and benign FCIs.
  
  
  CONCLUSIONS
  FCIs are observed in a not negligible number of patients who undergo (18)F-FDG-PET or PET/CT studies with a high risk of malignant or premalignant lesions. SUV is not reliable as a tool to differentiate between malignant, premalignant and benign FCIs. Further investigation is warranted whenever FCIs are detected by (18)F-FDG-PET or PET/CT.
authors.affiliation: Department of Nuclear Medicine and PET/CT Center, Oncology Institute of Southern Switzerland, Bellinzona, Switzerland.
authors.forename: Giorgio
authors.initials: G
authors.lastname: Treglia
authors.affiliation: Institute of Nuclear Medicine, Catholic University of the Sacred Heart, Rome, Italy.
authors.forename: Silvia
authors.initials: S
authors.lastname: Taralli
authors.affiliation: Institute of Radiology, Catholic University of the Sacred Heart, Rome, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Salsano
authors.affiliation: School of Medicine, Catholic University of the Sacred Heart, Rome, Italy.
authors.forename: Barbara
authors.initials: B
authors.lastname: Muoio
authors.affiliation: Nuclear Medicine Research Center, Mashhad University of Medical Sciences, Mashhad.
authors.forename: Ramin
authors.initials: R
authors.lastname: Sadeghi
authors.affiliation: Department of Nuclear Medicine and PET/CT Center, Oncology Institute of Southern Switzerland, Bellinzona, Switzerland.
authors.forename: Luca
authors.initials: L
authors.lastname: Giovanella
keywords: PET/CT; colonic uptake; colorectal cancer; fluorodeoxyglucose; focal uptake; incidentaloma