Tumour Oxygenation Assessed by Polarographic Needle Electrodes and Bioenergetic Status Measured by 31P Magnetic Resonance Spectroscopy in Human Soft Tissue Tumours

Abstract

The purpose of this study was to evaluate the feasibility of polarographic oxygen electrode measurements and phosphorus magnetic resonance spectroscopy (³¹P-MRS) in extravisceral soft tissue tumours, designated to receive preoperative radiotherapy. Pretreatment tumour oxygenation was determined in 41 cases and ³¹P-MRS was amenable to lesions in 34 patients. Biopsies were characterized histopathologically as 25 primary soft tissue sarcomas (STS), 2 recurrent STS, 9 benign and 5 other malignancies. Evaluation of phosphorus (³¹P) spectra was possible in 11 cases. The oxygenation status of normal tissue was higher than that of tumours, whereas no difference was found between oxygenation status of benign lesions and that of STS. There was substantial variation between tumours in the median pO₂ and the bioenergetic status (β-NTP/Pi). No correlation was found between tumour pO₂ and volume (n = 25). Moreover, there was no correlation between β-NTP/Pi and the median tumour pO₂, the fraction of pO₂ values $2.5 mmHg or tumour volume (n = 10), respectively. In conclusion, oxygen electrode assessment was found to be a clinically applicable and feasible technique for measuring tumour oxygenation status, whereas the success of ³¹P-MRS in human neoplasms was limited by a very poor resolution in the phosphorus signal that allowed analysis of ³¹P spectra in 11 tumours out of 34 cases.