Chemical modification of tumour blood flow.

The preferential modification of tumour blood flow with chemical agents has been extensively investigated for the purpose of improving the treatment of tumours with ionizing radiation, chemicals and hyperthermia. In this paper I have utilized representative vasoactive drugs to demonstrate the various mechanisms via which tumour haemodynamics can be modified selectively. Chemicals which alter tumour blood flow by changing blood viscosity are also discussed. Of particular interest are the calcium entry blockers, flunarizine and verapamil, which have been shown to increase tumour blood flow, tumour oxygenation, tumour radiation sensitivity and the cytotoxicity of chemotherapeutic agents. These encouraging research results provide compelling evidence that these two drugs may prove to be useful adjuvants for radiation therapy.