Assessment of Treatment Response in Patients with Glioblastoma Using O-(2-18F-Fluoroethyl)-l-Tyrosine PET in Comparison to MRI

• DOI: 10.2967/jnumed.111.098590
• Publication Date: 2012-05-30T02:23:13Z
• Authors: Norbert Galldiks; Karl-Josef Langen; Richard Holy; Michael Pinkawa; Gabriele Stoffels; Kay W. Nolte; Hans J. Kaiser; Christan P. Filss; Gereon R. Fink; Heinz H. Coenen; Michael J. Eble; Marc D. Piroth
• Keywords: Temozolomide; Univariate analysis

The assessment of treatment response in glioblastoma is difficult with MRI because reactive blood–brain barrier alterations contrast enhancement can mimic tumor progression. In this study, we investigated the predictive value PET using <i>O</i>-(2-¹⁸F-fluoroethyl)-l-tyrosine (¹⁸F-FET PET) during treatment. <b>Methods:</b> a prospective 25 patients were by and ¹⁸F-FET after surgery (MRI-/FET-1), early (7–10 d) completion radiochemotherapy temozolomide (RCX) (MRI-/FET-2), 6–8 wk later (MRI-/FET-3). Maximum mean tumor-to-brain ratios (TBR_max TBR_mean, respectively) determined region-of-interest analyses. Furthermore, gadolinium contrast-enhancement volumes on (Gd-volume) images ratio greater than 1.6 (T_{vol 1.6}) calculated threshold-based volume-of-interest grouped into responders nonresponders according to changes these parameters at different cutoffs, influence progression-free survival overall was tested univariate multivariate analyses receiver-operating-characteristic <b>Results:</b> Early RCX, decrease both TBR_max TBR_mean highly significant independent statistical predictor for survival. Receiver-operating-characteristic analysis showed that between FET-1 FET-2 more 20% predicted poor survival, sensitivity 83% specificity 67% (area under curve, 0.75). Six eight weeks later, less significant, but an association T_{vol 1.6} PFS noted. contrast, Gd-volume had no <b>Conclusion:</b> Gd-volumes MRI, may be valuable parameter assess predict time.