Change of oxygen pressure in glioblastoma tissue under various conditions

Measurement of oxygen pressure (pO(2)) in tumor tissue is important, because pO(2) is a major factor for radiosensitivity in malignant glioma treatment. We attempted to elucidate the changes in pO(2) level in glioblastoma tissue of patients under various conditions. Eighteen patients with newly diagnosed glioblastoma were recruited to this study. Disposable Clark-type electrodes were inserted using CT guided stereotactic surgery under local anesthesia and left in the intra- and peritumoral regions. pO(2) was measured in patients under conditions of being awake and asleep, inhaling 100% O-2, being administered osmotic diuretics and following hyperbaric oxygen exposure (HBO). Peritumoral tissue had a significantly higher pO(2) value in both awake and sleeping patients. O-2 inhalation could not significantly increase the pO(2) level, whereas administration of osmotic diuretics induced an increase in pO(2) levels in peritumoral tissue alone. The pO(2) levels were significantly increased in both regions after HBO, and a high pO(2) level was maintained until 15 min after HBO in both regions. It is possible that the pO(2) level in peritumoral tissue is affected by intracranial pressure, whereas that in the intratumoral tissue is usually low. HBO was the optimal procedure for oxygenation, but its benefit was reduced over time.