Repeatability and prognostic impact of the pretreatment pO(2) histography in patients with advanced head and neck cancer.

Abstract

The purpose of this study was to evaluate the repeatability and the predictive relevance of the pretreatment pO(2) histography on the survival of patients with advanced head and neck cancer. From July 1995 to August 1998, polarographic pO(2) measurements of lymph node metastases before therapy were performed in altogether 60 patients with histologically proven squamous cell carcinoma of the head and neck using the Eppendorf histograph. Forty-one of 60 patients were treated with an accelerated-hyperfractionated radiotherapy regimen with or without simultaneous chemotherapy as part of a multicenter phase III study. In 23 of 60 patients, two repeated independent measurements of the same tumor were performed with a time interval of approximately 24 h between the two measurements. The multivariate analysis revealed the fraction of pO(2) values </=2.5 mmHg as the only significant prognostic factor for the survival (P=0.05) in the 41 study patients. No correlation was found between tumour oxygenation and the volume of the measured lymph node metastases or the haemoglobin concentration. The coefficient of variation of the repeated measurements representing the assay variability was 57-68% of the total variation. Our data support the concept of the relevance of the pretreatment tumour hypoxia for the prognosis of patients with head and neck cancer after fractionated radiotherapy. Because of the relative poor repeatability of the pO(2) histography and the small patient number, further studies are required to confirm this finding and to evaluate the most relevant oxygenation parameter for clinical endpoints.