gms | German Medical Science

Objective: Stereotactic radiosurgery (SRS) has been increasingly applied to atypical or anaplastic meningioma after surgery for a better local control instead of conventional fractioned radiation therapy or watch and wait. The aim of our study was the characterization of our patient cohort with atypical or anaplastic meningioma.

Methods: We retrospectively identified all the patients with atypical or anaplastic meningioma who were treated by SRS using Cyberknife (CK) in our institution between 2011 until the end of 2016. Subsequently, we analysed clinical data including previous surgical treatments and further adjuvant treatments including re-irradiation. We mainly focused our analysis on the local therapy effect based on imaging follow up for progression free survival (PFS) after SRS. Kaplan Meier analysis was also performed to estimate PFS.

Results: A total of 31 patients (28 with atypical and 3 with anaplastic meningioma) were identified. 35% of the patients were treated for multiple lesions. The median follow up period was 2.4 years with a range of 2 months to 7 years. 52% of the patients presented a recurrent tumor, in 37.5% as a local progression, in 50% as a distant recurrence and in 12.5% as both. All of these patients with recurrent tumors received Cyberknife retreatment. Overall, 16% of the patients received also a further surgery after cyberknife treatment. The median planning target volume (PTV) for the first treatment was 3.59 mm³ with a median prescription dose of 16 Gy for single fraction (range 15–17 Gy). The rate for the hypofractionation in our cohort was 13%. The estimated median progression free survival was 4.8 and 4.3 years for atypical and anaplastic meningeomas, respectively.

Conclusion: Treatment of the patients with atypical or anaplastic meningiomas represents despite surgical, medico-nuclear and radiation treatments still a complicated challenge with high local and distant failure rates. Nevertheless, aggressive multimodal management, including reoperation and re-irradiation, allows median survivals that well compare with those of currently published series. The real boundaries of efficacy of radiosurgery have to be further evaluated in a larger number of patients to establish the best treatment protocol.