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 surgeery 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> 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<0.1). Complications have been seen in 6 irradiated patients.