title: Assessment of response to neoadjuvant radiochemotherapy with F-18 FLT and F-18 FDG PET/CT in patients with rectal cancer.
abstract: OBJECTIVE
  The comparison of 2-deoxy-2-[18F]fluoro-D-glucose (F-18 FDG) and 3'-deoxy-3'-[18F]fluorothymidine (F-18 FLT) imaging in patients with rectal cancer before and after neoadjuvant radiochemotherapy (RCT) in relation to histopathology and immunohistochemistry obtained from surgery.
  
  
  METHODS
  20 consecutive patients (15 m, 5 f), mean age of 65 ± 10 years were included into this prospective study with a mean follow-up of 4.1 ± 0.8 years.
  
  
  RESULTS
  Among histopathological responders (n = 8 out of 20), posttreatment F-18 FLT and F-18 FDG scans were negative in 75 % (n = 6) and 38 % (n = 3), respectively. The mean response index (RI) was 61.0 % ± 14.0 % for F-18 FLT and 58.7 % ± 14.6 % for F-18 FDG imaging. Peritumoral lymphocytic infiltration (CD3 positive cells) was significantly related to posttreatment SUVmax in F-18 FDG but not F-18 FLT studies.
  
  
  CONCLUSIONS
  A significant decrease of SUVmax in F-18 FDG and F-18 FLT studies could be seen after RCT. Negative posttreatment F-18 FLT studies identified more histopathological responders.
authors.affiliation: Department of Nuclear Medicine and Endocrinology, Paracelsus Medical University Salzburg, Muellner Hauptstr. 48, 5020, Salzburg, Austria, g.rendl@salk.at.
authors.forename: Gundula
authors.initials: G
authors.lastname: Rendl
authors.forename: Lukas
authors.initials: L
authors.lastname: Rettenbacher
authors.forename: Johannes
authors.initials: J
authors.lastname: Holzmannhofer
authors.forename: Lidwina
authors.initials: L
authors.lastname: Datz
authors.forename: Cornelia
authors.initials: C
authors.lastname: Hauser-Kronberger
authors.forename: Gerd
authors.initials: G
authors.lastname: Fastner
authors.forename: Dietmar
authors.initials: D
authors.lastname: Öfner
authors.forename: Felix
authors.initials: F
authors.lastname: Sedlmayer
authors.forename: Christian
authors.initials: C
authors.lastname: Pirich
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D059248:Chemoradiotherapy; D015224:Dideoxynucleosides; D005260:Female; D019788:Fluorodeoxyglucose F18; D005500:Follow-Up Studies; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging; D020360:Neoadjuvant Therapy; D049268:Positron-Emission Tomography / Q000379:methods; D011446:Prospective Studies; D019275:Radiopharmaceuticals; D012004:Rectal Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology / Q000628:therapy*; D014057:Tomography, X-Ray Computed / Q000379:methods; D016896:Treatment Outcome
chemical_list: D015224:Dideoxynucleosides; D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18; C002854:alovudine