Cervix cancer oxygenation measured following external radiation therapy

Purpose: Tumor hypoxia may be an important factor predicting relapse following radiation therapy. This study was designed to determine the relationship between the oxygenation parameters measured using a polarographic oxygen electrode, prior to and during treatment in patients with cervix cancer, and to assess these results with regard to patient survival. Materials and Methods: Forty-three patients had pretreatment oxygen assays performed and measurements repeated following external beam radiation to a median dose of 50 Gy (range 2662 Gy), Stage distribution showed 15 patients in Stage II, 17 in Stage II, and 11 in Stage III. The median tumor size was 5 cm (range 3-10 cm). Results: The median proportion of pO(2) values <5 mm Hg (the HP5) was 41% following radiation, and the median pO(2) was 12 mm Hg. These results were not significantly different from the pretreatment HP5 or pO(2) of 37% and 12 mm Mg, respectively. Disease-free survival at 2 years was 50% in patients with posttreatment HP, less than or equal to 50%, compared to 60% when posttreatment HP5 was >50% (p = 0.35), Conclusions: Unlike pretreatment results, tumour oxygenation measured following external radiation does not appear to be a useful predictive assay in patients with cervical cancer. (C) 1998 Elsevier Science Inc.