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The Role of Dual-Time Combined 18-Fluorideoxyglucose Positron Emission Tomography and Computed Tomography in the Staging and Restaging Workup of Locally Advanced Rectal Cancer, Treated With Preoperative Chemoradiation Therapy and Radical Surgery

Journal Article · · International Journal of Radiation Oncology, Biology and Physics
 [1];  [2];  [3];  [4];  [5];  [6];  [7];  [3];  [2];  [4];  [8];  [2];  [9]
  1. Department of Radiotherapy, State Hospital, Rovigo (Italy)
  2. Nuclear Medicine Service, State Hospital, Rovigo (Italy)
  3. Department of Oncology, State Hospital, Rovigo (Italy)
  4. Department of Surgery, State Hospital, Rovigo (Italy)
  5. Department of Clinical Pathology, State Hospital, Rovigo (Italy)
  6. Department of GastroEnterology, State Hospital, Rovigo (Italy)
  7. Department of Radiology, State Hospital, Rovigo (Italy)
  8. Department of Medical Physics, State Hospital, Rovigo (Italy)
  9. Department of Psychiatry, State Hospital, Rovigo (Italy)

Purpose: In patients with locally advanced rectal cancer (LARC) staging and, after preoperative chemo-radiation therapy (CRT), restaging workup could be useful to tailor therapeutic approaches. Fluorine-18-fluorodeoxyglucose positron emission tomography ([{sup 18}F]FDG-PET) is a promising tool for monitoring the effect of antitumor therapy. This study was aimed to evaluate the possible role of dual time sequential FDG-PET scans in the staging and restaging workup of LARC. Methods and Materials: Eighty-seven consecutive patients with LARC were enrolled. CRT consisted of external-beam intensified radiotherapy (concurrent boost), with concomitant chemotherapy PVI 5-FU (300mg/m{sup 2}/day) followed 8-10 weeks later by surgery. All patients underwent [{sup 18}F]FDG-PET/CT before and 5-6 weeks later after the completion of CRT. Measurements of FDG uptake (SUV{sub max}), and percentage of SUV{sub max} difference (Response Index = RI) between pre- and post-CRT [{sup 18}F]FDG-PET scans were evaluated. Results: Six of 87 patients were excluded due to protocol deviation. Following CRT, 40/81 patients (49%) were classified as responders according to Mandard's criteria (TRG1-2). The mean pre-CRT SUV{sub max} was significantly higher than post-CRT (15.8, vs 5.9; p < 0.001). The mean RI was significantly higher in responders than in nonresponder patients (71.3% vs 38%; p = 0.0038). Using a RI cut-off of 65% for defining response to therapy, the following parameters have been obtained: 84.5% sensitivity, 80% specificity, 81.4% positive predictive value, 84.2% negative predictive value, and 81% overall accuracy. Conclusion: These results suggest the potential role of [{sup 18}F]FDG-PET in the restaging workup after preoperative CRT in LARC. RI seems the best predictor to identify CRT response.

OSTI ID:
21276944
Journal Information:
International Journal of Radiation Oncology, Biology and Physics, Journal Name: International Journal of Radiation Oncology, Biology and Physics Journal Issue: 5 Vol. 74; ISSN IOBPD3; ISSN 0360-3016
Country of Publication:
United States
Language:
English