The Role of Postoperative External Irradiation for the Incompletely Resected Meningiomas

Kim, Tae Hyun; Yang, Dae Sik; Kim, Chul Young; Choi, Myung Sun

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.