Intra-operative radiation therapy for malignant brain tumours: Rationale, method, and treatment results of cerebral glioblastomas

Abstract

In radiation therapy for malignant brain tumours, the dose of radiation that can be safely delivered to a tumour is limited by the radiation tolerance of the adjacent normal brain tissue. Among various radiation modalities to produce local tumour eradication without unacceptable complications, we chose a large, single irradiation dose during the operation (intra-operative radiation therapy, IORT). In contrast to X-ray or Cobalt-60 gamma ray irradiation, IORT with a high-energy electron beam delivered by the Shimadzu 20 MeV betatron provides acceptable dose homogeneity with rapid fall-off of the radiation dose beyond the treatment volume. Thus, IORT has the advantage of precise demarcation of the target volume, minimum damage to surrounding normal tissues, and a high absorbed target dose (15-25 Gy in 5-10 min). On the basis of our experience with 170 patients treated by IORT, we established the treatment indications and method in patients with malignant brain tumours. IORT with a dose of 15-25 Gy was delivered to widely resected tumours followed by external radiation therapy. No acute or subacute complications were observed. Treatment results of 30 patients with glioblastoma treated by IORT (mean 18.3 Gy) combined with external radiation therapy (mean 58.5 Gy) resulted in a median survival of 119 weeks and a 2-year survival rate of 61%.

Intraoperative Radiation Therapy and Chemotherapy for Huge Choroid Plexus Carcinoma in an Infant —Case Report—

“…The benefits of adjuvant chemotherapy are still under discussion. " We describe a case of large choroid plexus carcino ma managed by radical resection, intraoperative radi ation therapy (IORT), 14,20,21) and chemotherapy using agents selected by in vitro chemosensitivity testing.'') Case Report A 2-month-old boy was admitted to our hospital be cause of head enlargement.…”

Intraoperative Radiotherapy in Patients with High-Grade Glioma in Comparison to Conventionally Treated Patients – a Matched-Pair Analysis

“…Especially in Japan favorable results were reported [2,[16][17][18][19]. Matsutani et al [2] treated 30 patients with glioblastoma combined with external radiation therapy. They calculated a median survival time of 119 weeks and a 2-year survival rate of 61%.…”

“…Since controlled randomized clinical trials are lacking, it is still unclear whether IORT produces a significant benefit for the patients. The very favorable results from Matsutani et al [2] are based on a high selection of patients with excellent performance status before therapy, younger age, and small superficial tumors. In the absence of prospective clinical studies an acceptable comparison between therapy modalities can be made by a matched-pair analysis.…”

“…Preliminary results of intraoperative radiotherapy (IORT) for patients with malignant brain tumors indicate that this method is feasible, but so far it is unclear whether IORT results in a survival benefit [1][2][3][4]. Controlled clinical trials comparing IORT and conventional radiotherapy are missing for patients with high-grade brain tumors.…”

Differential Diagnosis Between Radiation Necrosis and Glioma Progression Using Sequential Proton Magnetic Resonance Spectroscopy and Methionine Positron Emission Tomography

“…2,11,17,25,26,30) This progress has provided longer survival time for the patients after the initial treatment, but has also given rise to other problems such as differentiation of radiation necrosis from recurrent tumor. 10,21) The salvage methodology has not been established, so advances in post-initial treatment may further improve outcome.…”