Fractionated stereotactic radiation therapy for benign meningiomas of the cavernous sinus

Abstract

We analysed our long-term experience with fractionated stereotactic radiotherapy (FSRT) in patients with benign meningiomas of the cavernous sinus. Between 01/1990 and 02/2002, 53 patients with a median age of 53.8 years (23.7–74.5 years) were treated with FSRT for benign meningiomas of the cavernous sinus. Male/ female ratio was 42/11 patients. Karnofsky performance score was 90% median. Tumor distribution was: World Health Organization (WHO) grade I 45.3%, WHO grade II 1.9% (1/53 patients), and unknown histology 52.8%. Twenty-one patients received radiotherapy as primary treatment, 15 following surgery (subtotal resection: 8, biopsy only: 7). Seventeen patients were treated for recurrent disease. The median target volume was 34.2cc (range, 1.0–386.8cc). Target volume was greater than 30cc in 28 patients. Median total dose was 57.6Gy with 1.8Gy per fraction five times a week. Median follow-up period was 5.6 years (range, 1.1–14.1 years). All patients were followed for more than 12 months, 46/53 patients (86.8%) for more than 36 months. Overall local tumor control was 98.1% (52/53 meningiomas). Thirty-seven out of 53 patients (69.8%) had stable disease based on CT/MRI, while 28.3% had a reduction of tumor volume of more than 50%. Local tumor failure was observed in one of 53 patients with a meningeoma WHO grade II. Overall survival for patients with WHO grade I meningiomas was 95.5% after 5 years. Two patients died after 2.8 and 4.1 years after radiotherapy due to cardiac failure. Forty-eight out of 53 patients (90.6%) showed clinical symptoms before radiotherapy like reduced vision (34%), diplopia (43.4%), loss of visual fields (17%), trigeminal hyp-/dysaesthesia (26.4%) or exophthalmia (3.8%). Most patients had more than one clinical symptom. One patient showed an improvement on preexisting exophthalmia. There was one patient with a new trigeminal hypaesthesia resulting of treatment and one patient showed recurrent lacrimation of one eye on the side of the irradiated cavernous sinus meningeoma. Clinically significant late toxicity (RTOG grade II) like reduced vision or trigeminal hypaesthesia was seen in 3.8% after FSRT. No late toxicity RTOG > grade III occurred. These data demonstrate that FSRT is an effective and safe treatment modality for local control of benign meningioma of the cavernous sinus with a minimal risk of significant late toxicity