title: Can (18)F-FDG PET/CT scan change treatment planning and be prognostic in recurrent colorectal carcinoma? A prospective and follow-up study.
abstract: OBJECTIVE
  To prospectively study whether in patients with resected primary colorectal cancer fluorine- 18-fluorodeoxyglucose positron emission tomography/computed tomography ((18)F-FDG PET/CT) examination could diagnose the stage, specify treatment procedure and be prognostic.
  
  
  METHODS
  This prospective study included 75 patients with resected primary colorectal adenocarcinoma referred for (18)F-FDG PET/CT to the National PET Center, at the Clinical Center of Serbia, Belgrade, from January 2010 to May 2013. Findings of (18)F-FDG PET/CT were compared to findings of subsequent histopathological examinations or with results of clinical and imaging follow-up. Patients were followed after PET/CT examination for a mean follow-up time of 16.7±5.9 months.
  
  
  RESULTS
  In the detection of recurrent disease (18)F-FDG PET/CT showed overall sensitivity, specificity, PPV, NPV and accuracy of 96.6%, 82.4%, 94.9%, 87.5% and 93.3%, respectively. In the detection of stages I and II sensitivity, specificity and accuracy of (18)F-FDG PET/CT were: 88%, 96.6% and 94.7%, respectively, and in the detection of stages III and IV sensitivity, specificity and accuracy were 94.9%, 87.5% and 93.3%, respectively. These findings prevented or changed intended surgical treatment in 12/32 cases. Univariate and multivariate Cox proportional regression analyses revealed that metastatic recurrence (stages III and IV) was the only and independent prognostic factor of disease progression during follow-up (P=0.012 and P=0.023, respectively). Although, survival seemed better in patients with local recurrence compared to metastatic recurrent disease, this difference did not reach significance (Log-rank test; P=0.324). In addition, progression-free survival time was significantly longer in patients in whom (18)F-FDG PET/CT scan led to treatment changes (Log-rank test; P=0.037).
  
  
  CONCLUSIONS
  (18)F-FDG PET/CT was sensitive and accurate for the detection and staging of local and metastatic recurrent colorectal carcinoma, with higher specificity in the detection of local recurrences. The (18)F-FDG PET/CT scan induced treatment changes in 30/75 patients, including 12/32 patients in which surgical treatment was previously planned, and progression free survival time was significantly longer in these patients.
authors.affiliation: Center of Nuclear Medicine, Clinical Center of Serbia, Visegradska 26, 11000 Belgrade, Republic of Serbia. cale_odl@yahoo.com.
authors.forename: Vera
authors.initials: V
authors.lastname: Artiko
authors.forename: Strahinja
authors.initials: S
authors.lastname: Odalovic
authors.forename: Dragana
authors.initials: D
authors.lastname: Sobic-Saranovic
authors.forename: Milorad
authors.initials: M
authors.lastname: Petrovic
authors.forename: Milica
authors.initials: M
authors.lastname: Stojiljkovic
authors.forename: Nebojsa
authors.initials: N
authors.lastname: Petrovic
authors.forename: Nebojsa
authors.initials: N
authors.lastname: Kozarevic
authors.forename: Isidora
authors.initials: I
authors.lastname: Grozdic-Milojevic
authors.forename: Vladimir
authors.initials: V
authors.lastname: Obradovic
mesh_terms: D000368:Aged; D002277:Carcinoma / Q000000981:diagnostic imaging* / Q000473:pathology; D015179:Colorectal Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology; D018450:Disease Progression; D018572:Disease-Free Survival; D005260:Female; D019788:Fluorodeoxyglucose F18; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging; D015999:Multivariate Analysis; D009364:Neoplasm Recurrence, Local / Q000175:diagnosis; D049268:Positron-Emission Tomography / Q000379:methods*; D011379:Prognosis; D016016:Proportional Hazards Models; D011446:Prospective Studies; D012008:Recurrence; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013997:Time Factors; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D019788:Fluorodeoxyglucose F18