Direct Comparison of Gamma Knife Radiosurgery and Microsurgery for Small Size Meningiomas.

BACKGROUND: Patients with small (<3 cm) intracranial meningiomas can be either observed or treated. Treatment can be either radiosurgery or microsurgery if and when tumor progression occurs. We compared local tumor growth control and recurrence-free survival (RFS) of microsurgical resection and radiosurgery in small intracranial meningiomas and identified predictors of unfavorable outcome.

METHODS: A retrospective review (2005-2016) was performed of 90 consecutive patients with intracranial meningiomas who underwent either microsurgery (n = 31) or Gamma Knife radiosurgery (GKRS) (n = 59). The study population was evaluated clinically and radiographically after treatment.

RESULTS: GKRS in meningiomas showed a significantly higher percentage of local control of tumor growth compared with microsurgery (P = 0.02) 5 and 10 years (P = 0.003) after treatment. The median RFS was also significantly higher in the GKRS group compared with the microsurgery group (P = 0.04). There was no difference in RFS between Simpson grade I resection and GKRS (P = 0.69). In univariate analysis, RFS after procedures was significantly affected by tumor involvement of cranial nerves, presence of comorbidities, and preoperative Karnofsky performance scale score ≤70. In multivariate analysis, only preoperative Karnofsky performance scale score ≤70 was a predictor of unfavorable outcome.

CONCLUSIONS: GKRS offers a high rate of tumor control and longer RFS that is comparable to Simpson grade I resection. Subtotal resection is not a good choice for small meningiomas. The treatment procedure should be tailored according to the presence of comorbidities and the maximum benefit for the patient.