Reirradiation with stereotactic radiosurgery for vestibular schwannomas - a systematic review and meta-analysis

Stereotactic radiosurgery (SRS) is a widely used treatment modality for vestibular schwannomas due to its non-invasive nature and high tumor control rates. However, some patients experience tumor progression after treatment. In this setting, reirradiation with SRS represents a potential treatment option. This systematic review and meta-analysis evaluates the evidence for reirradiation of vestibular schwannomas with SRS.

This systematic literature review and meta-analysis investigates the efficacy and safety of reirradiation with SRS for vestibular schwannoma and was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA).

A total of 806 studies were screened and 35 included, comprising 394 reirradiated patients. The median time from first treatment to reirradiation was 45 months (range: 12 - 65 months). Reirradiation with SRS, applying a median marginal/prescription dose of 12 Gy, achieved an estimated local control of 95% (95% confidence interval (CI): 92 - 97%, I² = 29.62%, p = 0.10). Trigeminal and facial nerve deterioration rates after repeat SRS were 7% (95% CI: 4 - 10%, I² = 0.0%, p = 0.44) and 6% (95% CI: 3 - 8%, I² = 0.0%, p = 0.53), respectively. Serviceable hearing after reirradiation with SRS was rare (5%, 95% CI: 2 - 8%, I² = 0.0%, p = 0.46). Among patients with serviceable hearing before reirradiation, 43% maintained it after treatment (95% CI: 29 - 57%, I² = 65.71%, p = 0.00). The risk of bias across all studies was high.

Reirradiation with SRS appears to be a safe and effective salvage treatment for progressive vestibular schwannomas. Prospective studies are warranted to define the optimal dose, timing, and dose constraints for reirradiation.