title: 18Fluoro-deoxy-glucose positron emission tomography in assessing tumor response to preoperative chemoradiation therapy for locally advanced rectal cancer.
abstract: BACKGROUND
  This study aims to evaluate the efficacy of (18)F-FDG PET in assessing tumor response after preoperative chemoradiation therapy (CRT) for rectal cancer.
  
  
  METHODS
  Maximum standardized uptake value (SUV) was measured for 37 patients who underwent (18)F-FDG PET before and 4 weeks after completion of preoperative CRT. Pre-SUV, post-SUV, the difference between pre- and post-SUV (ΔSUV), and reduction rate (RR) were correlated with tumor response.
  
  
  RESULTS
  A lower mean post-SUV and a higher mean RR were shown in good tumor response (T-downstaging(+) and tumor regression grade 1, 2). Considering pathologic complete response (pCR), the mean post-SUV and the mean RR were significantly different between pCR (+) patients (N = 13) and pCR (-) patients (N = 24) (2.7 vs. 4.8, P < 0.001, 73.9% vs. 58.7%, P = 0.009). With a 3.35 cut-off value for the post-SUV by receiver operating characteristic analysis, 84.6% sensitivity, 79.2% specificity, and 81.2% overall accuracy were obtained for discriminating between pCR (+) and pCR (-) (area under the curve = 0.885, P < 0.001).
  
  
  CONCLUSIONS
  (18)F-FDG PET is potentially useful as a method for assessing tumor response after preoperative CRT for rectal cancer. Post-SUV and RR were significantly associated with pathological treatment response, especially in pCR.
authors.affiliation: Department of Surgery, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Hyuk
authors.initials: H
authors.lastname: Hur
authors.forename: Nam Kyu
authors.initials: NK
authors.lastname: Kim
authors.forename: Mijin
authors.initials: M
authors.lastname: Yun
authors.forename: Byung Soh
authors.initials: BS
authors.lastname: Min
authors.forename: Kang Young
authors.initials: KY
authors.lastname: Lee
authors.forename: Ki Chang
authors.initials: KC
authors.lastname: Keum
authors.forename: Jung Bai
authors.initials: JB
authors.lastname: Ahn
authors.forename: Hoguen
authors.initials: H
authors.lastname: Kim
mesh_terms: D000230:Adenocarcinoma / Q000000981:diagnostic imaging / Q000188:drug therapy / Q000473:pathology / Q000532:radiotherapy; D000328:Adult; D000368:Aged; D000970:Antineoplastic Agents / Q000008:administration & dosage; D002166:Camptothecin / Q000008:administration & dosage / Q000031:analogs & derivatives; D003082:Colectomy; D003131:Combined Modality Therapy / Q000379:methods; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D000077146:Irinotecan; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D049268:Positron-Emission Tomography / Q000379:methods*; D057234:Preoperative Period; D011446:Prospective Studies; D012372:ROC Curve; D019275:Radiopharmaceuticals; D012004:Rectal Neoplasms / Q000000981:diagnostic imaging / Q000188:drug therapy / Q000473:pathology / Q000532:radiotherapy; D016896:Treatment Outcome
chemical_list: D000970:Antineoplastic Agents; D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18; D000077146:Irinotecan; D002166:Camptothecin