Microsurgical resection and Gamma Knife radiosurgery for olfactory groove meningiomas: A retrospective cohort study

Olfactory groove meningiomas (OGMs) are common anterior skull base tumors. While microsurgery is standard, it risks complications like olfactory impairment. Upfront Gamma Knife radiosurgery (GKRS) is an alternative, but comparative studies against surgery as an initial treatment are scarce. This retrospective study (2009–2023) compared 59 patients undergoing initial microsurgery with 54 receiving upfront GKRS for OGMs at West China Hospital. Tumor control rates, Karnofsky Performance Status (KPS), and neurological function outcomes were analyzed to evaluate the appropriate treatment strategy for OGMs. Long-term tumor control was similar between initial microsurgery and upfront GKRS (Ten-year tumor control rates: 91.9% vs. 84.2%, P = 0.99). Upfront GKRS was associated with better patient quality of life (Mean KPS scores 93.1 vs. 87.0, P < 0.001), predicted by treatment modality (P = 0.027) and baseline KPS (P < 0.001). Olfactory preservation was superior after GKRS (98.0% vs. 86.4%, P = 0.048). Initial microsurgery (OR = 6.36, P = 0.032) and pre-treatment anosmia (OR = 91.05, P < 0.001) were independent predictors of post-treatment anosmia. Both upfront GKRS and microsurgery offer excellent long-term OGM control. Treatment should be individualized. GKRS provides lower morbidity and superior olfactory preservation, making it preferable for smaller tumors without significant mass effect. Surgery remains necessary for larger or compressive lesions.