The Role of Postoperative External Irradiation for the Incompletely Resected Meningiomas / 대한방사선종양학회지

ABSTRACT

PURPOSE: The aim of this study is to look for the possible efficacy of postoperative external irradiation for incompletely resected meningiomas. METHODS AND MATERIALS From August 1981 to January 1997, forty-four patients with intracranial meningioma were treated by postoperative external irradiation. Of the 44 meningiomas, 18 transitional, 13 meningotheliomatous, 6 hemangiopericytic, 4 atypical, 2 fibroblastic and 1 malignant meningioma were identified. We classified all patients into two groups by the histology. The benign group was consisted of the meningotheliomatous, transitional and fibroblastic types. The malignant group was consisted of the atypical, hemangiopericytic and malignat types. In the means of surgery, 37 patients were resected incompletely and 7 patients were managed by biopsy only. After surgery, all patients were received postoperative external irradiation. Radiotherapy was deliverd using Co-60 or 4 MV photon beam to a total dose of 50 to 66 Gy (mean dose 57.4 Gy) with a 1.8 to 2 Gy per fraction. The median follow-up was 48 months (range 21~101 months). Multivariate analysis of the influence by age, sex, location, histology and radiation dose on local control has been done using Cox's proportional hazard model. RESULTS: 5-year local control rate was 93.8% for the benign histology and 51.8% for the malignant histology (p=0.0110) and overall local control rate at 5 years was 87.4%. The analysis of the prognostic factors, such as age, sex, location, and radiation dose were not significant except for the histology. CONCLUSION: Adjuvant postoperative external irradiation appears to be significantly improved local control in the patients with incompletely resected meningiomas.