Blood flow and oxygenation status of human tumors: Clinical investigations

There is a large body of evidence suggesting that blood flow and oxygenation of human tumors are important research topics which may explain, in particular, resistance to radiation and to many antineoplastic drugs, which can limit the curability of solid tumors by radiotherapy and chemotherapy. This manuscript reviews the clinical investigations which have been performed regarding blood flow and oxygenation status of human tumors in radiation oncology. The possible uses and limitations of the prognostic significance and the changes under therapy measuring blood flow and oxygenation in human tumors were discussed. In addition, several approaches were summarized, which can improve the microvascular O₂ availability and perfusion-limited O₂ delivery. The clinical data concerning the prognostic significance of blood flow, vascular function and oxygenation of human tumors are relevant for patient selection in clinical oncology. Strategies to improve traditional cancer therapy by modulation of the oxygenation status remain quite promising but more critical research and sophisticated clinical studies are necessary before its true potential is known.