The Role of Stereotactic Radiosurgery in Patients With Foramen Magnum Meningiomas

BACKGROUND AND OBJECTIVES: Management options for foramen magnum meningiomas (FMM) include observation, attempts at surgical resection, and radiation therapy. The authors report the single-institution long-term experience of the use of primary or adjuvant stereotactic radiosurgery (SRS) for FMMs. METHODS: A total of 40 FMM patients (29 female) underwent SRS between 1987 and 2022. The median age at SRS was 62.0 (range: 30-82) years. Ten patients had prior surgical resection (2 gross total resections, 8 subtotal resections), whereas 4 patients had prior fractionated radiation therapy. Tumors were located at the anterior midline (5 patients), anterior lateral (25 patients), posterior midline (5 patients), and posterior lateral (5 patients) quadrants. The median prescription dose was 12.5 Gy (range: 10-16), and the median cumulative FMM tumor volume treated was 2.3 cc (range: 0.35-12.0). RESULTS: The median follow-up time was 88.0 months (range: 12-253). Fourteen patients had a follow-up >5 years, and 12 additional patients had >10-year follow-ups. Complete imaging response was noted in 1 patient, partial regression was noted in 13 patients, and 25 patients had no further growth. One patient had tumor progression 9 months after initial SRS and then underwent repeat surgical resection. The overall local tumor control rate was 98%. A total of 35 patients had improved or stable neurological symptoms after SRS, and 5 patients reported delayed worsening of symptoms. Ten patients were deceased at the last clinical follow-up. The median overall survival was 102 months (range: 41-164). None of the patients died related to central nervous system disease progression. No post-SRS adverse radiation effects were detected. CONCLUSION: Progressive FMM presents a management challenge. In this experience, SRS effectively prevented local tumor progression and preserved neurological function. Our experience supports the role of SRS as a primary or adjuvant management strategy.