Definition and manipulation of tumor oxygenation

Abstract

AbstractUsing a computer‐controlled polarographic oxygen electrode system, the oxygen tension profiles of two rat tumors, the 13762 mammary carcinoma and the 9L gliosarcoma, and one murine tumor, the FSall fibrosarcoma, were determined under eight different conditions. The oxygen profiles were characterized by four parameters related to tumor oxygenation and by three parameters related to tumor hypoxia. In the rat 13762 mammary carcinoma tumor median pO2 and the percent of pO2 were correlated with tumor volume under three different conditions. With these tumors the decrease in percent of pO2 readings in the tumor <5 mmHg appeared to correlate with the enhancement in therapeutic response of the rat tumors to single dose radiation therapy and of the mouse tumor to single doses of melphalan or cyclophosphamide. Both the perfluorochemical emulsion (Oxygent(tm) CA) with carbogen breathing and the polymerized bovine hemoglobin with air or carbogen breathing were effective in increasing the oxygenation of these three tumors. Pentoxifylline administration especially along with carbogen breathing increased the oxygenation of the tumors. These studies indicate that the decrease in the percent of the tumor which is most severely hypoxic may be predictive of improved therapeutic response in tumors treated with oxygen‐dependent or oxygen‐responsive therapies and oxygen delivery agents. © Wiley‐Liss, Inc.