Stereotactic LINAC radiosurgery for incompletely resected or recurrent atypical and anaplastic meningiomas

Abstract

The optimal management of subtotally resected or recurrent malignant meningiomas remains controversial. We evaluated the efficacy of linear accelerator (LINAC) radiosurgery for atypical and anaplastic meningiomas after incomplete resection or treatment of recurrences. Between August 1990 and December 2003, 16 patients with 28 meningiomas WHO II and III were treated by stereotactic LINAC radiosurgery at our institution. The median radiological follow-up was 60.3 months, respectively (range: 7.2-173.9 months). Fourteen tumors in nine patients were classified as WHO II and 14 tumors in seven patients as WHO III. The median surface dose was 14 Gy (range: 10-15 Gy) with a median tumor volume of 4.8 ml (range: 0.51-51.4 ml). Clinical condition improved in four patients, remained unchanged in nine and deteriorated in one. Tumor shrinkage was seen in eight of 28 meningiomas and a stable disease in 12. Eight of 28 meningiomas showed local tumor progression. The overall tumor control rate (TCR) was 84%, 70%, 70% after 3, 5, 10 years. According to grading the corresponding TCR after 3, 5, 10 years was 91%, 81%, 81% for grade II and 77%, 60%, 60% for grade III meningiomas. Overall progression-free survival (PFS) was 74%, 67%, 58% after 3, 5, 10 years. According to grading the PFS after 3, 5, 10 years was 88%, 75%, 75% for grade II meningiomas and 57%, 57%, 43% for grade III meningiomas. Our results show the efficacy and safety of LINAC radiosurgery for incompletely resected or recurrent malignant meningiomas with a relatively high local tumor control and low morbidity.