Wide dural radiation therapy for NF2-SWN associated meningiomatosis

Neurofibromatosis type 2-related schwannomatosis (NF2-SWN) patients frequently present with intracranial meningiomatosis (multiple meningiomas), but optimal management remains unclear. We evaluated the safety and efficacy of wide dural radiation therapy (WDRT) in this population.

Ten NF2-SWN patients treated with WDRT between March 2018 and December 2022 were reviewed. Endpoints included local control (LC) and progression-free survival (PFS) from the date of WDRT completion and acute toxicity. Progressive disease was defined as a >20% increase in tumor diameter or new lesion development.

Median age was 41 years (range 25-53) with a median follow-up of 45.8 months. All patients initiated WDRT for growing lesions or worsening symptoms. Median doses were 54 Gy to gross lesions and tumor bed and 48 Gy to the wide dural field (30 fractions). Ninety-one meningiomas with sizes greater than 5 mm received doses 48 Gy or higher with no infield progression. The 2-year LC rate was 100%, though follow-up remains limited for definitive long-term assessment. Three patients (30%) experienced outfield progression (median 31.3 months): two in intentionally untreated lesions (to be later treated with either surgery or radiosurgery) and one marginal recurrence at the edge of the supratentorial field. Two patients experienced acute grade 2 toxicity including nausea and headache.

WDRT provides excellent local control and adequate safety profiles in NF2-SWN patients with meningiomatosis. Further prospective studies with a predefined target volume are warranted to validate our findings.