Vascular architecture and hypoxic profiles in human head and neck squamouscell carcinomas

Tumour oxygenation and vasculature are determinants for radiation treatment outcome and prognosis in patients with squamous cell carcinomas of the hea d and neck. in this study we visualized and quantified these factors which may provide a predictive tool for new treatments. Twenty-one patients with stage III-IV squamous cell carcinomas of the head and neck were intravenous ly injected with pimonidazole, a bioreductive hypoxic marker. Tumour biopsi es were taken 2 h later. Frozen tissue sections were stained for vessels an d hypoxia by fluorescent jmmunohistochemistry. Twenty-two sections of biops ies of different head and neck sites were scanned and analysed with a compu terized image analysis system. The hypoxic fractions Varied from 0.02 to 0. 29 and were independent from T- and N-classification, localization and diff erentiation grade. No significant correlation between hypoxic fraction and vascular density was observed. As a first attempt to categorize tumours bas ed on their hypoxic profile, three different hypoxia patterns are described . The first category comprised tumours with large hypoxic, but viable, area s at distances even greater than 200 mu m from the vessels. The second cate gory showed a typical band-like distribution of hypoxia at an intermediate distance (50-200 mu m) from the vessels with necrosis at greater distances. The third category demonstrated hypoxia already within 50 mu m from the ve ssels, suggestive for acute hypoxia, This method of multiparameter analysis proved to be clinically feasible. The information on architectural pattern s and the differences that exist between rumours can improve our understand ing of the tumour micro-environment and may in the future be of assistance with the selection of (oxygenation modifying) treatment strategies. (C) 200 0 Gander Research Campaign.