title: Early change in glucose metabolic rate measured using FDG-PET in patients with high-grade glioma predicts response to temozolomide but not temozolomide plus radiotherapy.
abstract: OBJECTIVE
  To compare the ability of positron emission tomography (PET) to predict response to temozolomide vs. temozolomide plus radiotherapy.
  
  
  METHODS
  Nineteen patients with high-grade glioma (HGG) were studied. Patients with recurrent glioma received temozolomide 75 mg/m2 daily for 7 weeks (n=8). Newly diagnosed patients received temozolomide 75 mg/m2 daily plus radiotherapy 60 Gy/30 fractions over 6 weeks, followed by six cycles of adjuvant temozolomide 200 mg/m2/day (Days 1-5 q28) starting 1 month after radiotherapy (n=11). [18F]Fluorodeoxyglucose ([18F]FDG) PET scan and magnetic resonance imaging (MRI) were performed at baseline, and 7 and 19 weeks after initiation of temozolomide administration. Changes in glucose metabolic rate (MRGlu) and MRI response were correlated with patient survival.
  
  
  RESULTS
  In the temozolomide-alone group, patients who survived>26 vs. <or=26 weeks showed a greater reduction in MRGlu measured at 7 weeks with median changes of -34% and -4%, respectively (p=0.02). PET responders, defined as a reduction in MRGlu>or=25%, survived longer than nonresponders with mean survival times of 75 weeks (95% CI, 34-115 vs. 20 weeks (95% CI, 14-26) (p=0.0067). In the small group of patients studied, there was no relationship between MRI response and survival (p=0.52). For patients receiving temozolomide plus radiotherapy, there was no difference in survival between PET responders and nonresponders (p=0.32).
  
  
  CONCLUSIONS
  Early changes in MRGlu predict response to temozolomide, but not temozolomide plus radiotherapy.
authors.affiliation: Wolfson Molecular Imaging Centre, Academic Department of Radiation Oncology, The University of Manchester, Christie Hospital NHS Trust, Manchester, United Kingdom. natalie.charnley@mmic.man.ac.uk
authors.forename: Natalie
authors.initials: N
authors.lastname: Charnley
authors.forename: Catharine M
authors.initials: CM
authors.lastname: West
authors.forename: Carolyn M
authors.initials: CM
authors.lastname: Barnett
authors.forename: Catherine
authors.initials: C
authors.lastname: Brock
authors.forename: Graeme M
authors.initials: GM
authors.lastname: Bydder
authors.forename: Mark
authors.initials: M
authors.lastname: Glaser
authors.forename: Ed S
authors.initials: ES
authors.lastname: Newlands
authors.forename: Ric
authors.initials: R
authors.lastname: Swindell
authors.forename: Julian
authors.initials: J
authors.lastname: Matthews
authors.forename: Pat
authors.initials: P
authors.lastname: Price
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D018906:Antineoplastic Agents, Alkylating / Q000627:therapeutic use*; D001921:Brain / Q000378:metabolism; D001932:Brain Neoplasms / Q000188:drug therapy / Q000378:metabolism / Q000532:radiotherapy; D003131:Combined Modality Therapy / Q000379:methods; D003606:Dacarbazine / Q000031:analogs & derivatives* / Q000627:therapeutic use; D004334:Drug Administration Schedule; D005260:Female; D019788:Fluorodeoxyglucose F18; D005910:Glioma / Q000188:drug therapy / Q000378:metabolism / Q000532:radiotherapy; D005947:Glucose / Q000378:metabolism*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local; D049268:Positron-Emission Tomography; D019275:Radiopharmaceuticals; D011879:Radiotherapy Dosage; D000077204:Temozolomide; D016896:Treatment Outcome
chemical_list: D018906:Antineoplastic Agents, Alkylating; D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18; D003606:Dacarbazine; D005947:Glucose; D000077204:Temozolomide