OXYGEN-TENSION DISTRIBUTION IN HEAD AND NECK CARCINOMAS AFTER PERORAL OXYGEN-THERAPY

EBLE MJ;LOHR F;WANNENMACHER M

1995

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Abstract

Background: It has been shown that the response on radiotherapy in human tumors is correlated to the oxygen supply. Polarographic needle electrodes offer a feasible tool to determine the oxygen tension distribution in human tumors. The peroral administration of oxygen-enhanced water may be able to overcome the radioresistance in reducing hypoxic regions in larger tumors and will be analyzed. Patients and Methods: Oxygen tension distributions were determined in clinically fixed lymph node 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) From a pooled histogram (n=200) median pO(2), mean pO(2) and hypoxic fraction could be calculated and compared. Results: The determined pO(2) tension values showed a typical distribution for squamous cell carcinomas of the head and neck region with the proof of containing hypoxic tumor cells. After administration of oxygen-enhanced water 2 patients revealed only a marginal increase in oxygen supply. A moderate improvement in tissue oxygenation was observed in 3 patients, combined with a therapeutically relevant shift of pO(2) values from the low pO(2) classes (<10 mm Hg) to medium pO(2) classes. In 1 patient an impressive increase in the overall oxygen tissue tension could be observed. The overall mean and median pO(2) values increased after peroral oxygen therapy (POT) from 14.4 to 23.3 mm Hg and from 22.3 to 30.2 mm Hg, respectively. The hypoxic fraction was significantly reduced. Conclusion: The peroral administration of oxygen-enhanced water is a feasible technique to increase the oxygen supply to tumors. The therapeutic role should be evaluated ina larger clinical trial, combined with the invasive determination of oxygen tension distributions. The reduced hypoxic fraction seems to be promising in therapeutic irradiation.