[Polarographic detection of reoxygenation of lymph node metastases in the initial phase of primary radio- and radiochemotherapy in patients with advanced squamous epithelial carcinomas of the head and neck].

The therapeutic effect of radiotherapy depends amongst other things on the degree of oxygenation of tumour tissue. Epithelial carcinomas of the head-neck region exhibit considerable hypoxic areas which vary markedly between individuals and not encompassed by current staging and grading. It is assumed that during radiation treatment a reoxygenation of hypoxic tumour cells takes place. It was investigated wether the occurrence of reoxygenation could be determined by invasive oxygen partial pressure measurements in lymph node metastases. Using a needle probe inserted transcutaneously into a lymph node polarographic oxygen determinations (Eppendorf pO2-Histiograph) were made on 13 patients with advanced oro- and hypopharyngeal carcinomas before therapy and after a week of accelerated radio- or radiochemotherapy. Low pO2 values before treatment (median 13.5 mmHg, average 20.3 mmHg) and a hypoxic fraction (pO2 < 10 mmHg) of 45.2% indicated manifest tumour hypoxia. After the first week of treatment a significant increase in the median- (24.1 mmHg) and the average pO2 (28.2 mmHg) as well as a reduction in the hypoxic fraction (27%) were observed. Invasive pO2 histiography fulfils the requirements for a method to confirm tumour hypoxia in head-neck tumours. The results obtained indicate that reoxygenation occurs during the initial phases of radio- and radio-chemotherapy.