Perfluorocarbon Emulsion and Oxygen with Concomitant Radiation Therapy in Primary High Grade Brain Tumors

Abstract

High grade gliomas represent 40%–50% of primary intracranial tumors, and the prognosis for these patients remains poor, with a median survival time of <1 year (Karlsson and Brady 1987). The Brain Tumor Study Group’s clinical trial, BTSG 69–01, was the first randomized trial to show that postoperative radiation therapy significantly increased median survival time in patients with high grade gliomas when compared with neurosurgical treatment alone (Walker et al. 1978). Although the quality of life in these patients treated with high dose radiation therapy is acceptable, the vast majority of patients succumb to their tumors within 1 year from the termination of treatment. Since the observation over 30 years ago that poorly oxygenated cells are approximately two to three times more resistant to radiation, many attempts have been made to overcome this relative radioresistance of the radiobiologically hypoxic cells thought to exist in many human tumors. A recent study examining the patterns of failure following radiation treatment for high grade brain tumors revealed that 78% of unifocal tumors recurred within 2 cm of the enhancing edge of the tumor, as demonstrated by the CT scan (Wallner et al. 1989). This study highlights the failure of high doses of radiation to sterilize pockets of presumably radiobiologically hypoxic cells. It has been hypothesized that either the tumor has outgrown its blood supply or the external pressure of the tumor has caused capillaries to become collapsed. The failure, therefore, of radiotherapy in the treatment of high grade gliomas has been attributed, at least in part, to the presence of radiobiologically hypoxic areas (Nelson et al. 1986).