FDG PET Predicts Glioblastoma Survival After Treatment

Hossein Jadvar, MD, PhD, MPH, MBA


May 23, 2017

Adjuvant chemoradiation therapy after maximal surgical resection is the standard of care for individuals with glioblastoma, a devastating cancer.[1] MRI is often used to follow these patients. However, MRI is nonspecific and cannot reliably distinguish between residual/recurrent tumors after therapy and pseudoprogression (reaction to therapy). PET with 18F-fluorodeoxyglucose (FDG), although nonspecific for cancer, may provide useful diagnostic information.

The Study

A new report by Carlos Leiva-Salinas and colleagues[2] of the University of Virginia describes a retrospective investigation of 56 patients with glioblastoma who underwent FDG PET for the evaluation of enhancing residual lesions at brain MRI postoperatively, followed by chemoradiation therapy. The authors correlated the residual lesion FDG uptake (termed "SUVr" and calculated as the ratio of the lesion's maximum standardized uptake value [SUVmax] relative to healthy white matter) with the primary endpoint of overall survival from the point of the date of the PET study, and the results were stratified on the basis of SUVr.

The researchers found a significant association between overall survival and the residual lesion SUVr. The median survival was 23.1, 13.5, 10.1, and 7.5 months for an SUVr < 1.7, between 1.7 and 2.0, between 2.0 and 2.5, and > 2.5, respectively.


The objective of this investigation was to assess the association between an outcome of interest—in this case, overall survival—and level of glucose metabolism (as measured by SUVr) on FDG PET of the enhancing residual lesions seen on brain MRI after primary treatment for glioblastoma. The investigation was retrospective, with all its recognized limitations. But it was clear from this study that although post-therapy MRI may show enhancing residual lesions suspected for recurrence, it is FDG PET that can provide the clinically relevant and useful important prognostic information in this clinical setting.

The association between lesion glucose metabolism and outcome has been demonstrated for many tumors. The prevailing reasoning is that higher tumor metabolism reflects a higher-grade tumor and worse prognosis compared with tumors that have low FDG uptake. Such prognostic information can help in the selection of patients for novel therapy clinical trials, with the hope of improving the overall dismal outcome in this devastating disease.



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