Tumor Blood Flow-Characterization, Modifications, and Role in Hyperthermia

Abstruct-The differential blood flow rateof normaland tumor tissues plays a critical role in determining the effectiveness of hyperthermia alone or in combination with radiation and chemotherapy. The objective of this paper is to summarize the data on tumor blood flow rate during normothermia and hyperthermia, and to discuss the use of pharmacological agents in modifying the tumor blood flow rate for therapeutic benefits. After a brief review of various physical, physiological, biochemical, and biological factors that determine the effectiveness of hyperthermia in cancer treatment, various methods of blood flow measurements will be outlined. The following section will be devoted to the tumor blood flow rate during normothermia. Next will be discussion of changes in tumor blood flow rate at elevated temperatures. Finally, the possibility of modifying tumor blood flow rate by the use of vasoactive agents will be discussed. Throughout this paper, outstanding problems in the measurements and alterations of blood flow will be identified and some directions for future research will be suggested.