Fractionated radiation therapy of intracranial meningiomas: 15 years experience

To evaluate the long-term results of external fractionated radiation therapy (RT) in the treatment of intracranial meningiomas. From january 1981 to December 1996, 156 patients with intracranial meningiomas were treated with external fractionated RT. Median age was 57. Indications for radiation therapy were as follows: completely excised histologically aggressive tumors (12 patients); incomplete surgical resection (37 patients); medically inoperable or basilar tumors where operation would involve considerable danger or permanent neurological damage (77 patients); and, tumor recurrences (30 patients). Most patients were irradiated with 6 to 9 MV photon beams. A three to four-field technique with coned-down portals was used. Since 1993, 71 patients had a three dimensional dosimetry. Doses were calculated on the 95 % or 98 % isodoses, all fields were treated every day, five days a week, for a median total dose of 50 Gy (1.8 Gy/Fraction). Median follow-up from radiation therapy was 40 months. Acute tolerance was excellent, an early clinical improvement during radiation therapy was noted in 19 patients (17.8 %). Clinical improvement or stabilization was observed in 130 patients (83,4 %), Radiologically, local control was obtained in 124 cases (79.4 %) and tumor recurrences occurred in 21 cases (ten progressions in the treated volume, five borderline, six new locations). Overall and cause specific-survival rates were 75 % and 89 % at five years, and 45 76 % at 10 years, respectively. These results reassess the role of fractionated RT in the treatment of intracranial meningiomas. Long-term tolerance is excellent for a majority of patients. The study of recurrences confirms the importance of the definition of the target volume, and asks questions about total given doses. (authors)