Fractionated external-beam radiation therapy for meningiomas of the cavernous sinus

Purpose: Despite advances in microsurgical technique, many cavernous sinus meningiomas remain unresectable or only partially resectable, prompting referral of patients for radiation therapy. Stereotactic radiosurgery is recommended as therapy at some institutions. We evaluated our experience with fractionated radiotherapy to permit comparison with single-fraction radiosurgery. Materials and Methods: Between July 1985 and January 1998, 21 women and 7 men were treated for primary (21) or recurrent (7) cavernous sinus meningiomas. Of these, 22 tumors were subtotally resected and 6 were unresectable. Of the 28 lesions, 26 were categorized histologically as benign (16), aggressive-benign (7), or malignant (3); 2 were not biopsied. All patients were treated with fractionated photon irradiation to a median dose of 53.1 Gy. We assessed prognostic factors for overall (OS) and progression- free survival (PFS), including age, gender, presentation (primary vs. recurrent), extent of surgical resection, radiotherapy dose, and technique. Influence of radiotherapy dose and technique on acute and late treatment toxicities was analyzed. Results: One patient died of disease and 2 others were alive with progressive disease at last follow-up, yielding 8-year actuarial OS and PFS of 96% and 81%, respectively. Univariate analysis showed that none of the prognostic factors tested was significantly associated with OS or PFS. There were two late side effects of treatment: an orbital sac fibrosis and a 6-month decline of cognitive function documented by formal neuropsychiatric testing. Neither radiotherapy dose nor technique significantly influenced late toxicity. Conclusion: For unresectable or subtotally resected cavernous sinus meningiomas, fractionated radiotherapy provides patients with excellent progression-free survival and minimal treatment-related toxicity.