The prognostic value of [¹²³I]-vascular endothelial growth factor ([¹²³I]-VEGF) in glioma

Recent studies have shown that tumor vascular endothelial cells and various tumor cells overexpress receptors for vascular endothelial growth factor (VEGF). The aim of this study was to investigate the prognostic value of [¹²³I]-VEGF scintigraphy in patients with histologically verified brain tumors. 23 consecutive patients (9 women and 14 men aged 30-83 years, mean age 56.6 ± 14.4 years) with histopathologically-verified primary brain tumors were included in the study. All patients had undergone [¹²³I]-VEGF scintigraphy. SPECT examinations of brain were performed 30 min and 18 h after injection. Additional [¹¹C]-methionine PET ([¹¹C]-MET PET) was performed in eight of the 23 patients. Both [¹²³I]-VEGF and [¹¹C]-MET PET were evaluated visually and semiquantitatively by tumor-to-normal brain uptake ratio (T/N ratio). Thresholds of the T/N ratio were evaluated by analysis of receiver operating characteristics (ROC). Overall survival (OS) was estimated using the Kaplan-Meier method. World Health Organization (WHO) grade IV glioma lesions showed [¹²³I]-VEGF uptake 18 h after the injection, whereas other brain tumors of grade II or III showed negative results. There was no significant difference in the tumor size between VEGF positive and VEGF negative tumors. Patients with [¹²³I]-VEGF T/N ratio threshold <1.32 showed significantly longer survival than patients with T/N ratio ≥ 1.32 (2680 days vs 295 days; P < 0.05). In the subgroup of 16 grade IV glioma patients, significant OS differences were found using a T/N ratio of 1.75 as threshold (T/N ratio < 1.75: 720 days; T/N ≥ 1.75: 183 days; P < 0.05). Significant difference (P < 0.05) was also found in [¹¹C]-MET PET T/N ratios between the grade IV glioma (mean T/N ratio: 3.71) and the grade II or III glioma (mean T/N ratio: 1.74). Our results suggest that [¹²³I]-VEGF scintigraphy may be useful for visualization of tumor angiogenesis. In addition, [¹²³I]-VEGF may provide relevant prognostic information in patients with glioma. (orig.)