The role of radiotherapy in the treatment of subtotally resected benign meningiomas.

Thirty-six patients with benign meningioma were treated for primary or recurrent disease by subtotal resection and external beam irradiation from 1968-1986 at Massachusetts General Hospital. Comparison is made with 79 patients treated by subtotal surgery alone from 1962-1980. Progression-free survival for 17 patients irradiated after initial incomplete surgery was 88% at 8 years compared with 48% for similar patients treated by surgery alone (p = 0.057). 16 patients incompletely resected at time of first recurrence were irradiated and 78% were progression-free at 8 years while 11% of a similar group treated by surgery alone were progression free (p = 0.001). Long term overall survival was high and similar in both control and study groups. Two patients were irradiated at second recurrence and 1 patient at third recurrence. Twenty-five patients were treated with photons alone and have a median follow-up of 57 months, 6 patients have recurred at doses 45-60 Gy. Eleven patients were treated with combined 10 MV photons and 160 MV protons utilizing 3-D treatment planning. These patients have been followed for a median of 53 months and none have failed to date. Eight of 11 received 54-60.4 Gy and 3/11 greater than 64.48 Gy. Sex, age, pathology grade and score, surgery and timing of radiation therapy were not associated with significant differences in failure patterns within the irradiated study group (p less than 0.1). Complications have been seen in 6 irradiated patients.