title: Increased tryptophan uptake on PET has strong independent prognostic value in patients with a previously treated high-grade glioma.
abstract: BACKGROUND
  Previously, we demonstrated the high accuracy of alpha-[(11)C]methyl-L-tryptophan (AMT) PET for differentiating recurrent gliomas from radiation injury. The present study evaluated the prognostic value of increased AMT uptake in patients with previously treated high-grade glioma.
  
  
  METHODS
  AMT-PET was performed in 39 patients with suspected recurrence of World Health Organization grades III-IV glioma following surgical resection, radiation, and chemotherapy. Mean and maximum standardized uptake values (SUVs) and unidirectional AMT uptake (K) were measured in brain regions suspicious for tumor and compared with the contralateral cortex (ie, background). Optimal cutoff thresholds for 1-year survival prediction were determined for each AMT parameter and used for calculating the prognostic value of high (above threshold) versus low (below threshold) values for post-PET overall survival (OS).
  
  
  RESULTS
  In univariate analyses, 1-year survival was strongly associated with 3 AMT parameters (SUVmax, SUVmean, and tumor-to-background K-ratio; odds ratios: 21.3-25.6; P ≤ .001) and with recent change in MRI contrast enhancement (odds ratio: 14.7; P = .02). Median OS was 876 days in the low- versus 177 days in the high-AMT groups (log-rank P < .001). In multivariate analyses, all 3 AMT parameters remained strong predictors of survival: high AMT values were associated with unfavorable 1-year survival (binary regression P ≤ .003) and shorter overall survival in the whole group (Cox regression hazard ratios: 5.3-10.0) and in patients with recent enhancement change on MRI as well (hazard ratios: 7.0-9.3; P ≤ .001).
  
  
  CONCLUSIONS
  Increased AMT uptake on PET is highly prognostic for 1-year and overall survival, independent of MRI contrast enhancement and other prognostic factors in patients with a previously treated high-grade glioma.
authors.affiliation: PET Center and Translational Imaging Laboratory, Children's Hospital of Michigan, Detroit Medical Center, Detroit, MI (D.O.K., O.M., C.J.); Department of Neurology, Wayne State University, Detroit, Michigan (G.R.B., C.J.); Department of Neurosurgery, Wayne State University, Detroit, Michigan (S.M.); Department of Oncology, Wayne State University, Detroit, Michigan (S.M.); Department of Pathology, Wayne State University, Detroit, Michigan (W.J.K.); Department of Pediatrics, Wayne State University, Detroit, Michigan (O.M., C.J.); Department of Radiology, Wayne State University, Detroit, Michigan (N.L.R., O.M.); Karmanos Cancer Institute, Detroit, Michigan (S.M., N.L.R., W.J.K., G.R.B., C.J.).
authors.forename: David O
authors.initials: DO
authors.lastname: Kamson
authors.affiliation: PET Center and Translational Imaging Laboratory, Children's Hospital of Michigan, Detroit Medical Center, Detroit, MI (D.O.K., O.M., C.J.); Department of Neurology, Wayne State University, Detroit, Michigan (G.R.B., C.J.); Department of Neurosurgery, Wayne State University, Detroit, Michigan (S.M.); Department of Oncology, Wayne State University, Detroit, Michigan (S.M.); Department of Pathology, Wayne State University, Detroit, Michigan (W.J.K.); Department of Pediatrics, Wayne State University, Detroit, Michigan (O.M., C.J.); Department of Radiology, Wayne State University, Detroit, Michigan (N.L.R., O.M.); Karmanos Cancer Institute, Detroit, Michigan (S.M., N.L.R., W.J.K., G.R.B., C.J.).
authors.forename: Sandeep
authors.initials: S
authors.lastname: Mittal
authors.affiliation: PET Center and Translational Imaging Laboratory, Children's Hospital of Michigan, Detroit Medical Center, Detroit, MI (D.O.K., O.M., C.J.); Department of Neurology, Wayne State University, Detroit, Michigan (G.R.B., C.J.); Department of Neurosurgery, Wayne State University, Detroit, Michigan (S.M.); Department of Oncology, Wayne State University, Detroit, Michigan (S.M.); Department of Pathology, Wayne State University, Detroit, Michigan (W.J.K.); Department of Pediatrics, Wayne State University, Detroit, Michigan (O.M., C.J.); Department of Radiology, Wayne State University, Detroit, Michigan (N.L.R., O.M.); Karmanos Cancer Institute, Detroit, Michigan (S.M., N.L.R., W.J.K., G.R.B., C.J.).
authors.forename: Natasha L
authors.initials: NL
authors.lastname: Robinette
authors.affiliation: PET Center and Translational Imaging Laboratory, Children's Hospital of Michigan, Detroit Medical Center, Detroit, MI (D.O.K., O.M., C.J.); Department of Neurology, Wayne State University, Detroit, Michigan (G.R.B., C.J.); Department of Neurosurgery, Wayne State University, Detroit, Michigan (S.M.); Department of Oncology, Wayne State University, Detroit, Michigan (S.M.); Department of Pathology, Wayne State University, Detroit, Michigan (W.J.K.); Department of Pediatrics, Wayne State University, Detroit, Michigan (O.M., C.J.); Department of Radiology, Wayne State University, Detroit, Michigan (N.L.R., O.M.); Karmanos Cancer Institute, Detroit, Michigan (S.M., N.L.R., W.J.K., G.R.B., C.J.).
authors.forename: Otto
authors.initials: O
authors.lastname: Muzik
authors.affiliation: PET Center and Translational Imaging Laboratory, Children's Hospital of Michigan, Detroit Medical Center, Detroit, MI (D.O.K., O.M., C.J.); Department of Neurology, Wayne State University, Detroit, Michigan (G.R.B., C.J.); Department of Neurosurgery, Wayne State University, Detroit, Michigan (S.M.); Department of Oncology, Wayne State University, Detroit, Michigan (S.M.); Department of Pathology, Wayne State University, Detroit, Michigan (W.J.K.); Department of Pediatrics, Wayne State University, Detroit, Michigan (O.M., C.J.); Department of Radiology, Wayne State University, Detroit, Michigan (N.L.R., O.M.); Karmanos Cancer Institute, Detroit, Michigan (S.M., N.L.R., W.J.K., G.R.B., C.J.).
authors.forename: William J
authors.initials: WJ
authors.lastname: Kupsky
authors.affiliation: PET Center and Translational Imaging Laboratory, Children's Hospital of Michigan, Detroit Medical Center, Detroit, MI (D.O.K., O.M., C.J.); Department of Neurology, Wayne State University, Detroit, Michigan (G.R.B., C.J.); Department of Neurosurgery, Wayne State University, Detroit, Michigan (S.M.); Department of Oncology, Wayne State University, Detroit, Michigan (S.M.); Department of Pathology, Wayne State University, Detroit, Michigan (W.J.K.); Department of Pediatrics, Wayne State University, Detroit, Michigan (O.M., C.J.); Department of Radiology, Wayne State University, Detroit, Michigan (N.L.R., O.M.); Karmanos Cancer Institute, Detroit, Michigan (S.M., N.L.R., W.J.K., G.R.B., C.J.).
authors.forename: Geoffrey R
authors.initials: GR
authors.lastname: Barger
authors.affiliation: PET Center and Translational Imaging Laboratory, Children's Hospital of Michigan, Detroit Medical Center, Detroit, MI (D.O.K., O.M., C.J.); Department of Neurology, Wayne State University, Detroit, Michigan (G.R.B., C.J.); Department of Neurosurgery, Wayne State University, Detroit, Michigan (S.M.); Department of Oncology, Wayne State University, Detroit, Michigan (S.M.); Department of Pathology, Wayne State University, Detroit, Michigan (W.J.K.); Department of Pediatrics, Wayne State University, Detroit, Michigan (O.M., C.J.); Department of Radiology, Wayne State University, Detroit, Michigan (N.L.R., O.M.); Karmanos Cancer Institute, Detroit, Michigan (S.M., N.L.R., W.J.K., G.R.B., C.J.).
authors.forename: Csaba
authors.initials: C
authors.lastname: Juhász
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001932:Brain Neoplasms / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000378:metabolism / Q000401:mortality; D002250:Carbon Radioisotopes; D005260:Female; D005910:Glioma / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000378:metabolism / Q000401:mortality; D006801:Humans; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000378:metabolism / Q000401:mortality; D049268:Positron-Emission Tomography; D011379:Prognosis; D016019:Survival Analysis; D014364:Tryptophan / Q000031:analogs & derivatives / Q000493:pharmacokinetics*
chemical_list: D002250:Carbon Radioisotopes; D014364:Tryptophan
keywords: MRI; amino acid PET; high-grade glioma; survival; tryptophan