Visual and semiquantitative 11 C-methionine PET: An independent prognostic factor for survival of newly diagnosed and treatment naive gliomas

Abstract

Background

Few data exist regarding the prognostic value of L-[S-methyl- ¹¹C]methionine (MET) PET for treatment-naive gliomas.

Methods

A total of 160 glioma patients (89 men, 71 women, mean age: 45, range 18 - 84 yrs) underwent a MET PET prior to any therapy. The PET scans were evaluated visually and semiquantitatively by tumor to background (T/N) ratio thresholds chosen by ROC-Analysis. Additionally, isocitrate dehydrogenase 1-R132H (IDH1-R132H) immunohistochemistry was performed. Survival analysis was done using Kaplan-Meier estimate and Cox proportional hazard model.

Results

Significantly shorter mean survival times (7.2 vs. 8.6 yrs; p=0,024) were seen in patients with amino-acid avid gliomas (n=137) compared to visually negative tumors (n=33) in MET PET. T/N ratio thresholds of 2.1 and 3.5 were significantly associated with survival (10.3 vs. 7 vs. 4.3 yrs; p < 0.001). Mean survival differed significantly using the median T/N ratio of 2.4 as cut-off, independent of histopathology (p<0.01; mean survival: 10.2 ± 0.8 yrs versus 5.5 ± 0.6 yrs). In the subgroup of 142 glioma patients characterized by the IDH1-R132H status MET T/N ratio demonstrated a significant prognostic impact in IDH1-R132H wildtype astrocytomas and glioblastoma (p = 0.001). Additionally, multivariate testing revealed semiquantitative MET PET as an independent prognostic parameter for treatment-naive glioma patients without (p=0.031) and with IDH1-R132H characterization of gliomas (p=0.024; OR 1.57).

Conclusion

This retrospective analysis demonstrates the value of MET PET as a prognostic parameter on survival in treatment-naive glioma patients.

from #ORL-AlexandrosSfakianakis via ola Kala on Inoreader http://ift.tt/2gRSJko