title: Total 18F-FDG PET/CT Metabolic Tumor Volume Is Associated With Postoperative Biochemical Response in Patients With Metastatic Pheochromocytomas and Paragangliomas.
abstract: OBJECTIVE
  The aim of this pilot study was to determine if metabolic tumor volume (MTV) and total lesion glycolysis (TLG) could serve as predictors of biochemical remission and pharmacotherapy-free interval in patients with metastatic pheochromocytomas (PCCs) and paragangliomas (PGLs).
  
  
  BACKGROUND
  Patients with metastatic PCCs/PGLs have a high rate of biochemical recurrence, which can be associated with increased cardiovascular morbidity. Predictors of biochemical response are needed to guide and select patients who may benefit from therapy.
  
  
  METHODS
  Whole body MTV and TLG was calculated from preoperative 18F-FDG PET/CT scans and analyzed as marker of biochemical response and pharmacotherapy-free interval.
  
  
  RESULTS
  Seventeen patients underwent a total of 19 procedures, with a median follow-up time of 26.4 months. Whole body MTV of patients with biochemical recurrence (n = 13, mean 73.8  mL) was higher than those who had a biochemical response (n = 6, mean 14.7  mL, P = 0.05). Patients with low MTV (<37.2  mL) had an improved durable partial biochemical response (P < 0.05), and a statistical trend for complete biochemical remission (P = 0.07) and pharmacotherapy-free interval (P = 0.06). In 8 patients with metastatic disease outside the abdomen, 4 patients had less than 35% of their disease burden outside the abdomen and these patients had a more durable partial biochemical response compared to patients with greater than 35% of their disease burden outside the abdomen (P < 0.05).
  
  
  CONCLUSIONS
  Whole body MTV and TLG represents novel and valuable predictors of biochemical response for patients with metastatic PCCs and PGLs. A larger prospective study should be performed to validate these findings.
authors.affiliation: *Endocrine Oncology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD †Geisel School of Medicine at Dartmouth, Hanover, NH ‡PET Department, Clinical Center, National Institutes of Health, Bethesda, MD §Program in Reproductive and Adult Endocrinology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD.
authors.forename: Dhaval
authors.initials: D
authors.lastname: Patel
authors.forename: Amit
authors.initials: A
authors.lastname: Mehta
authors.forename: Naris
authors.initials: N
authors.lastname: Nilubol
authors.forename: William
authors.initials: W
authors.lastname: Dieckmann
authors.forename: Karel
authors.initials: K
authors.lastname: Pacak
authors.forename: Electron
authors.initials: E
authors.lastname: Kebebew
mesh_terms: D000310:Adrenal Gland Neoplasms / Q000000981:diagnostic imaging* / Q000378:metabolism / Q000601:surgery; D000328:Adult; D014408:Biomarkers, Tumor / Q000378:metabolism*; D005260:Female; D019788:Fluorodeoxyglucose F18; D006019:Glycolysis; D006801:Humans; D008297:Male; D064847:Multimodal Imaging; D009364:Neoplasm Recurrence, Local; D010235:Paraganglioma / Q000000981:diagnostic imaging* / Q000378:metabolism / Q000601:surgery; D010673:Pheochromocytoma / Q000000981:diagnostic imaging* / Q000378:metabolism / Q000601:surgery; D049268:Positron-Emission Tomography; D011379:Prognosis; D019275:Radiopharmaceuticals; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome; D047368:Tumor Burden; D051598:Whole Body Imaging
chemical_list: D014408:Biomarkers, Tumor; D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18