12 Years’ Experience with Intraoperative Radiotherapy (IORT) of Malignant Gliomas

Abstract

Even after surgery and radiotherapy, malignant gliomas still have a poor prognosis. The authors report on their experience with IORT in 71 patients. From May 1992 to February 2004, 71 patients with malignant gliomas were treated with IORT. 26 patients suffered from grade III gliomas, 45 patients from glioblastomas (GBM). IORT was carried out using a standard electron tube and 9- to 18-MeV electrons. 52/71 patients who were primarily treated received 20 Gy IORT + 60 Gy postoperative radiotherapy, 19/71 patients with recurrences only received IORT (20-25 Gy). The complication rates were 1.4% for wound infections and 5.6% for hemorrhage. Median disease-specific survival amounted to 14.9 months (gliomas III) and 14.2 months (GBM). The 2-year survival rates amounted to 26.9% (gliomas III) and 6.8% (GBM; p = 0.0296). Total versus subtotal resection had no significant influence on survival (p = 0.0741), nor had age, sex, tumor site, performance status, size, primary versus recurrence, and radiation dose. A comparison to a conventionally treated patient group did not show a significant survival improvement. 3 months after treatment, initial symptoms had improved in 59% (hemiparesis), 50% (aphasia), 50% (hemianopsia), and 60% (convulsions). IORT has been shown to be feasible; perioperative complication rates were not increased. Survival was generally not improved compared to a historical control group. Recurrences achieved the same survival as primary tumors, and GBM also had a slightly increased survival, thus being possible indications for IORT.