Lack of perfusion enhancement after administration of nicotinamide and carbogen in patients with glioblastoma: a 99mTc-HMPAO SPECT study.

Abstract

Nicotinamide (NAM) and carbogen both have been shown to enhance the radiation effect in rodent tumour models and are currently being tested in clinical trials. These agents have demonstrated to act against hypoxia and one of their underlying mechanisms could be an increase of tumour blood perfusion. To analyse the effect of both agents on normal brain perfusion and tumour perfusion in patients with glioblastoma. Nineteen patients with glioblastoma were studied with 99mtechnetium-hexamethylpropyleneamine oxime single photon emission computed tomography (99mTc-HMPAO SPECT) before and after administration of carbogen and/or NAM. Another six patients were studied with the same procedure but without any flow modulator and were used as controls. Although the variations between patients were large, no significant enhancement in mean tumour and normal brain perfusion could be demonstrated with NAM or carbogen compared to the control patients. Also no consistent changes in the mean perfusion ratio between tumour and surrounding normal brain were found, suggesting an absence of a selective perfusion effect. No significant influence of carbogen and/or NAM on tumour perfusion and normal brain perfusion could be detected with SPECT in patients with glioblastoma.