Primary Versus Salvage Stereotactic Radiosurgery for Patients With Olfactory Groove Meningiomas: A 35-Year Single-Institution Experience.

Background and objectives: Stereotactic radiosurgery (SRS) is an important management strategy for patients with olfactory groove meningiomas (OGMs). This study aimed to compare outcomes after primary SRS vs salvage SRS postresection in our institution over the past 35 years.

Methods: We reviewed the radiographic imaging of 2030 patients with meningiomas who underwent SRS between 1987 and 2022. Seventy-nine patients with OGM were identified. The median patient age at SRS was 62 years (range, 33-90 years). Forty-eight patients (60.76%) underwent primary SRS and 31 patients (39.24%) had previous resections. The median tumor volume was 4.30 cc (range, 0.19-26.90 cc), and the median margin dose prescribed at SRS was 13 Gy (range, 9-18 Gy). SRS protocol, neurological outcomes, overall survival, and local tumor control (LTC) were evaluated.

Results: The overall survival for all OGM patients was 17 years (range, 0.8-24.3 years). No patient deaths were related to intracranial tumor progression. Among primary SRS in 48 patients, 4 (8.33%) had tumor progression at a median time of 9.2 years (range, 0.4-12.3 years). For patients who underwent salvage SRS, 7 patients (22.5%) had delayed tumor progression at a median time of 6.4 years (range, 0.4-15.2 years) after SRS. Previous resection was found to be associated with anosmia (P < .01) and decreased LTC (P = .024). After primary SRS, 73% of patients experienced symptom improvement change. After salvage SRS 23 % of patients showed clinical improvement. In patients with peritumoral edema at SRS, the median percentage edema volume reduction was 82% after SRS.

Conclusion: SRS provided low risk long-term tumor control in OGM patients. Primary SRS provided superior LTC and preservation or improvement of olfactory function in most patients.