Can an ¹⁸F-ALF-NOTA-PRGD2 PET/CT Scan Predict Treatment Sensitivity to Concurrent Chemoradiotherapy in Patients with Newly Diagnosed Glioblastoma?

UNLABELLED: This study examined the value of a novel 1-step labeled integrin α(v)β3-targeting (18)F-AlF-NOTA-PRGD2 (denoted as (18)F-RGD) scan in assessing sensitivity to concurrent chemoradiotherapy (CCRT) in patients with newly diagnosed glioblastoma multiforme (GBM).

METHODS: Twenty-five patients with newly diagnosed GBM were enrolled in this study 3-5 wk after surgical resection. All participants were investigated with (18)F-RGD PET/CT on baseline (T1) and at the third week (T2) after the start of CCRT. Tumor volume, maximal and mean standardized uptake value of the tumor (SUVmax, SUVmean), and tumor-to-nontumor ratios of the tumor volume were obtained. The MRI treatment response was assessed at the 11th week (T3). The change in the lesion volume from T1 to T3 on MRI was used as an endpoint to evaluate the predictive ability of (18)F-RGD PET/CT.

RESULTS: With (18)F-RGD PET/CT imaging, we successfully visualized the residual lesions of GBM. Twenty-five and 23 (18)F-RGD PET/CT scans at baseline and the third week, respectively, were available for analysis. We found that (18)F-RGD PET/CT parameters, both pretreatment SUVmax on baseline (P< 0.05) and intratreatment SUVmax at the third week (SUV(maxT2)) (P< 0.05) and tumor-to-nontumor ratios at the third week (P< 0.05), were predictive of treatment sensitivity to CCRT. Additionally, the change of volume from T1 to T2 on MRI was also predictive (P< 0.05). According to receiver-operating-characteristic curve analysis, the most significant parameter was SUV(maxT2) (area under the curve, 0.846). The threshold of SUV(maxT2) was 1.35, and its sensitivity, specificity, and accuracy were 84.6%, 90.0% and 87.0%, respectively.

CONCLUSION: (18)F-RGD PET/CT allows for the noninvasive visualization of GBM lesions and the prediction of sensitivity to CCRT as early as 3 wk after treatment initiation.