Impact of salvage surgery with or without reirradiation for skull base meningiomas recurring after prior radiotherapy

Long-term follow-up of meningiomas has demonstrated recurrence rates ranging from 2.5% to 48% after 10 years, depending on histology grade. There are limited data available to guide the management of recurrent and previously irradiated skull base meningiomas, and challenges related to salvage surgery, reirradiation, and lack of clear systemic therapy strategies remain. In this study, the authors analyzed data from their experience with recurrent and previously irradiated meningiomas to assess the impact of salvage surgery and reirradiation on progression-free survival (PFS).A retrospective cohort study of 48 patients with recurrent and previously irradiated meningiomas who were treated between 1995 and 2021 was conducted. Data were extracted from medical records and included clinical, radiological, and pathologic reports. Patients were clustered according to WHO grades. The authors analyzed the complications related to reirradiation and salvage surgery and the impact of different treatment modalities on PFS using Cox proportional hazard ratios.Forty-eight patients (33 with WHO grade I, 11 with WHO grade II, and 4 with WHO grade III meningiomas) were treated for 143 recurrences after their first radiation treatment. For WHO grade I meningiomas, there was no change in tumor control rates with adjuvant repeat radiotherapy (HR 0.784, 95% CI 0.349-1.759; p = 0.55), and in terms of extent of resection (EOR), subtotal resection (STR) alone was associated with an increased risk of recurrence when compared with gross-total resection (GTR) (HR 3.38, 95% CI 1.268-9.036; p = 0.0189). For WHO grade II meningiomas, GTR did not significantly confer improved tumor control relative to STR (HR 0.42, 95% CI 0.17-1.037; p = 0.055), but adjuvant repeat radiotherapy after STR was associated with improved outcomes (HR 0.316, 95% CI 0.13-0.768; p = 0.0029). Finally, for WHO grade III meningiomas, EOR did not correlate with outcomes (HR 0.75, 95% CI 0.22-2.482; p = 0.588), but repeat radiotherapy alone was associated with a decreased odds of progression (HR 0.276, 95% CI 0.078-0.97; p = 0.0028).This study examined the impact of retreatment on PFS in a large cohort of patients with recurrent meningiomas that had been previously irradiated. At the time of recurrence, WHO grade I meningiomas exhibited improved PFS with GTR, subtotally resected WHO grade II meningiomas appeared to have improved PFS when reirradiated, and reirradiation in WHO grade III meningiomas showed improved PFS.