Single-fraction gamma-knife radiosurgery with or without previous surgery for cavernous sinus meningiomas: A single-center experience and systematic literature review

Abstract

Background: The most effective treatment method for meningiomas is surgical treatment. However, complete resection of cavernous sinus meningiomas is quite difficult. The biggest reasons for this are; narrow surgical corridor, the optic chiasm is the close relationship between the cranial nerves and anterior cerebral and internal carotid arteries. Gamma knife radiosurgery (GKRS) may be a good option in these lesions with high mortality and morbidity. Aim: This study aimed to evaluate and compare the early effects at a mean of 6 months and 3 years and outcomes between surgery followed by gamma knife radiosurgery (GKRS) and GKRS alone for cavernous sinus meningiomas. Methods: We included 20 patients with cavernous sinus meningioma treated via single fraction Leksell Gamma Knife Perfexion (Elekta Instruments; Stockholm, Sweden) between 2015 and 2018. The mean age of the patients was 54.95 (range: 32-77) years. Nine patients underwent primary surgery (for the resection of extracavernous components of the tumor) followed by GKRS (for the resection of intracavernous components of the tumor) (group A). Meanwhile, 11 patients were managed with GKRS alone (group B). The tumor volume ranged from 2.8 to 32.8 (mean: 14.76) cm3 and the isodose to the tumor margin from 10 to 13.5 (mean: 11.65) Gy. Results: In total, 20 patients were followed up at a mean time of 18.95 (range: 6-36) months. The mean Karnofsky Performance Score of the patients was 95.2%. The mean follow up times of groups A and B were 23.6 and 15 months, respectively. Meanwhile, only patients with a follow up time of at least 6 months were included in the study. The mean follow up time after GKRS in group A was 17.6 months. There was no change in the tumor volume in 15% of patients. In the remaining cases, the tumor volume decreased. The mean tumor regression rates were 82.2% in Group A and 17.7% in Group B. The tumor volume did not decrease in three patients (n = 1, group A and n = 2, group B). Cranial nerve deficits improved, worsened, and remained stable in 46.6%, 26.6%, and 26.6% of cases, respectively. The temporary morbidity rate was 10%. In group A, transient postoperative diabetes insipidus was observed in one patient and atelectasis in another. None of these complications affected the final status of patients. The mortality rate after treatment was 0%. Conclusion: Volume staged GKRS is safe and effective for cavernous sinus meningioma. GKRS is effective for long term tumor growth control and has a low complication rate. Hence, it is the preferred management strategy for tumors with a suitable volume (average tumor diameter: 3 cm or volume: 10 cm3 ). In tumors with a volume of more than 10 mL and/or without a 3 mm safety margin with the optical system, it is recommended to prepare for radiosurgery by cytoreducing the tumor volume surgically. Based on our opinion, the best results were obtained by GKRS to the intracavernous.