title: [(18)F]-FLT PET to predict early response to neoadjuvant therapy in KRAS wild-type rectal cancer: a pilot study.
abstract: OBJECTIVE
  This pilot study evaluated the utility of 3'-deoxy-3'[18F]-fluorothymidine ([(18)F]-FLT) positron emission tomography (PET) to predict response to neoadjuvant therapy that included cetuximab in patients with wild-type KRAS rectal cancers.
  
  
  METHODS
  Baseline [(18)F]-FLT PET was collected prior to treatment initiation. Follow-up [(18)F]-FLT was collected after three weekly infusions of cetuximab, and following a combined regimen of cetuximab, 5-FU, and radiation. Imaging-matched biopsies were collected with each PET study.
  
  
  RESULTS
  Diminished [(18)F]-FLT PET was observed in 3/4 of patients following cetuximab treatment alone and in all patients following combination therapy. Reduced [(18)F]-FLT PET following combination therapy predicted disease-free status at surgery. Overall, [(18)F]-FLT PET agreed with Ki67 immunoreactivity from biopsy samples and surgically resected tissue, and was predictive of treatment-induced rise in p27 levels.
  
  
  CONCLUSIONS
  These results suggest that [(18)F]-FLT PET is a promising imaging biomarker to predict response to neoadjuvant therapy that included EGFR blockade with cetuximab in patients with rectal cancer.
authors.affiliation: Vanderbilt University Institute of Imaging Science (VUIIS), Vanderbilt University Medical School, 1161 21st Ave. S., AA1105 MCN, Nashville, TN, 37232-2310, USA.
authors.forename: Eliot T
authors.initials: ET
authors.lastname: McKinley
authors.forename: Jennifer M
authors.initials: JM
authors.lastname: Watchmaker
authors.forename: A Bapsi
authors.initials: AB
authors.lastname: Chakravarthy
authors.forename: Jeffrey A
authors.initials: JA
authors.lastname: Meyerhardt
authors.forename: Jeffrey A
authors.initials: JA
authors.lastname: Engelman
authors.forename: Ronald C
authors.initials: RC
authors.lastname: Walker
authors.forename: M Kay
authors.initials: MK
authors.lastname: Washington
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Coffey
authors.forename: H Charles
authors.initials: HC
authors.lastname: Manning
mesh_terms: D000328:Adult; D000970:Antineoplastic Agents / Q000627:therapeutic use; D000068818:Cetuximab / Q000627:therapeutic use; D059248:Chemoradiotherapy; D015224:Dideoxynucleosides; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging / Q000379:methods; D020360:Neoadjuvant Therapy; D010865:Pilot Projects; D049268:Positron-Emission Tomography / Q000379:methods; D016283:Proto-Oncogene Proteins p21(ras) / Q000235:genetics; D019275:Radiopharmaceuticals; D012004:Rectal Neoplasms / Q000175:diagnosis / Q000000981:diagnostic imaging* / Q000235:genetics / Q000628:therapy*; D014057:Tomography, X-Ray Computed / Q000379:methods; D016896:Treatment Outcome
chemical_list: D000970:Antineoplastic Agents; D015224:Dideoxynucleosides; C117307:KRAS protein, human; D019275:Radiopharmaceuticals; D016283:Proto-Oncogene Proteins p21(ras); C002854:alovudine; D000068818:Cetuximab