Prognostic Significance of Dynamic ¹⁸F-FET PET in Newly Diagnosed Astrocytic High-Grade Glioma

Abstract

Despite advances in diagnosis and the use of different therapeutic regimens in astrocytic high-grade glioma (HGG), the prognosis for patients remains grim. Additional pretherapeutic information is needed to tailor management. To gain additional prognostic information at primary diagnosis, we investigated the value ofWe retrospectively evaluated 121 patients who had a primary diagnosis of astrocytic HGG (51 World Health Organization [WHO] grade III; 70 WHO IV) and underwent dynamic 18 F-FET PET before histopathologic assessment. We assessed static parameters (maximal and mean tumoral standardized uptake value corrected for mean background activity in the contralateral hemisphere [SUV max / BG and SUV mean /BG, respectively], biologic tumor volume) and dynamic time-activity curves, including minimal time to peak (TTP min ). The prognostic influence of PET parameters and other clinical parameters on progression-free and overall survival was evaluated using uni-and multivariate Cox regression and Kaplan-Meier survival estimates. Results: In the group overall, median progression-free survival and overall survival were 12.2 and 21.9 mo. SUV max /BG, SUV mean /BG, and biologic tumor volume were significantly higher in WHO IV than in WHO III gliomas; median TTP min was 12.5 min in both groups. On univariate analysis, the factors age, WHO grade, O6-methylguanine-DNA methyltransferase promoter methylation status, contrast enhancement, initial treatment, and TTP min showed prognostic significance, with WHO grade, O6-methylguanine-DNA methyltransferase status, age, and TTP min remaining significant in the multivariate analysis. WHO grade and TTP min reached a similar fit for the prognostic evaluation. The prognosis of WHO III astrocytoma with an early TTP min of 12.5 min or less did not differ significantly from that of glioblastoma. Conclusion: Early TTP min is associated with worse outcome in patients with newly diagnosed astrocytic HGG. In the preoperative setting, TTP min can be a valuable noninvasive prognostic marker with comparable significance to WHO grade. Additionally, TTP min can help identify highly aggressive WHO III astrocytoma tumors and may help in adjusting standard treatment toward an individualized, risk-adapted therapy regime.

Late Pseudoprogression in Glioblastoma: Diagnostic Value of Dynamic O-(2-[18F]fluoroethyl)-L-Tyrosine PET

“…Similarly, the presence of curve patterns type II and III were predictive for true progression. TTP of 18 F-FET uptake has already been described as a helpful parameter for determining malignant progression in patients with low-grade glioma (9) and as a prognostic marker in high-grade glioma (22). In our series of patients TTP confirmed these finding by showing significant differences between true tumor progression and late PsP.…”

18F-FET PET Uptake Characteristics in Patients with Newly Diagnosed and Untreated Brain Metastasis

“…Whether dynamic PET parameters before further therapies do have a prognostic value at initial diagnosis, such as shown in primary gliomas (14,15), has to be evaluated in prospective settings. Additionally, all metastatic lesions showed time-activity curves characteristic for brain neoplasms, whereas no time-activity curve with a shape specific for vascular structures was seen.…”

“…Time-activity curve grades 1-2 were then classified as increasing time-activity curves and grades 3-5 as decreasing timeactivity curves. Additionally, the TTP was assessed in each slice within the tumor and the shortest TTP in at least 2 consecutive slices was defined as TTP min , as previously published (15). At the FZJ, dynamic 18 F-FET PET imaging was performed as described elsewhere (23).…”

“…Furthermore, patterns of timeactivity-curves and minimal time-to-peak (TTP min ) values derived from dynamic 18 F-FET PET provide more detailed information on glioma characteristics. For example, it has been demonstrated that dynamic 18 F-FET PET parameters have a high prognostic value in newly diagnosed low-and high-grade glioma (14,15). In secondary cerebral neoplasms, a few PET studies on pretreated brain metastases are currently available and have assessed the value of amino acid PET for the differentiation of recurrent disease from radiation-induced changes after radiotherapy (13,(16)(17)(18)(19).…”

Serial 18F-FET PET Imaging of Primarily 18F-FET–Negative Glioma: Does It Make Sense?

“…During recent years, 18 F-FET PET has been increasingly used to optimize and individualize the specific therapy: 18 F-FET PET has shown its value for biopsy guidance and planning of surgery and radiotherapy (4)(5)(6). Furthermore, dynamic 18 F-FET PET has shown utility for the estimation of tumor grade (7)(8)(9) and a remarkably high prognostic value in newly diagnosed glioma using the analysis of the timeactivity curves including the parameter minimal time to peak (TTP min ), for which short TTP min was associated with worse outcome (10,11). Besides these clinically relevant features at primary diagnosis, 18 F-FET PET imaging was shown to improve disease monitoring by early identification of tumor recurrence and progression and discrimination from posttherapeutic changes (12)(13)(14)(15)(16)(17).…”