EXPERIMENTAL STUDIES ON THE POSSIBLE INFLUENCE OF INVASIVE OXYGEN MEASUREMENTS ON TUMOR RADIOSENSITIVITY

The effects of tissue damage associated with invasive pO(2) measuremen ts on radiation sensitivity were investigated using a xenografted squa mous cell carcinoma model. For the tumour cure experiments, single dos e irradiations were given following different regimens of polarographi c pO(2) measurements associated with different degrees of mechanical t issue damage. With a dose of 32 Gy, 57% of animals were cured. Followi ng 3 tracks of needle measurements, 73% of tumours were locally contro lled, and 75% were cured after 8 needle tracks. The polarographic meas urements gave virtually identical oxygenation data for recurrent or cu red rumours (both median pO(2) 1.0 mmHg), respectively. There was thus no evidence of decreased radiosensitivity associated with tissue dama ge after invasive pO(2) measurements. The pre-therapeutic oxygenation status gave no evidence for a prediction of radiation response on an i ndividual basis.