Intranasal administration of POH increased the overall survival of patients with recurrent GBM in comparison with historical untreated controls, but especially patients with secondary GBM and primary GBM with tumor localized in deep regions of the brain. The side effects of POH treatment were almost nonexistent, even in patients treated for over 4 years.

This study suggests that: (1) patients with recurrent gliomas with localization in the basal ganglia survive significantly longer than those with tumors at lobar localization; (2) presence of PTBE contributes to symptoms, likely to be implicated in the morbidity and invading potential of malignant gliomas. These findings support the theory that interaction between glioma cells at distinct brain microenvironment can influence the oncobiological behavior of glioma cells and ultimately to the prognosis.