OXYGEN-TENSION DISTRIBUTION IN HEAD AND N ECK CARCINOMAS AFTER PERORAL OXYGEN-THERAPY

Background: It has been shown that the response on radiotherapy in hum an tumors is correlated to the oxygen supply. Polarographic needle ele ctrodes offer a feasible tool to determine the oxygen tension distribu tion in human tumors. The peroral administration of oxygen-enhanced wa ter may be able to overcome the radioresistance in reducing hypoxic re gions in larger tumors and will be analyzed. Patients and Methods: Oxy gen tension distributions were determined in clinically fixed lymph no de metastases in 6 patients suffering from a carcinoma of the base of the tongue (n=2), larynx (n=2), hypopharynx and tonsillar fossa before and immediately after drinking oxygen-enhanced water (20 mg/l O-2) Fr om a pooled histogram (n=200) median pO(2), mean pO(2) and hypoxic fra ction could be calculated and compared. Results: The determined pO(2) tension values showed a typical distribution for squamous cell carcino mas of the head and neck region with the proof of containing hypoxic t umor cells. After administration of oxygen-enhanced water 2 patients r evealed only a marginal increase in oxygen supply. A moderate improvem ent in tissue oxygenation was observed in 3 patients, combined with a therapeutically relevant shift of pO(2) values from the low pO(2) clas ses (<10 mm Hg) to medium pO(2) classes. In 1 patient an impressive in crease in the overall oxygen tissue tension could be observed. The ove rall mean and median pO(2) values increased after peroral oxygen thera py (POT) from 14.4 to 23.3 mm Hg and from 22.3 to 30.2 mm Hg, respecti vely. The hypoxic fraction was significantly reduced. Conclusion: The peroral administration of oxygen-enhanced water is a feasible techniqu e to increase the oxygen supply to tumors. The therapeutic role should be evaluated ina larger clinical trial, combined with the invasive de termination of oxygen tension distributions. The reduced hypoxic fract ion seems to be promising in therapeutic irradiation.