Patterns of Recurrence in Skull Base Meningioma after Secondary Gamma Knife Radiosurgery

Introduction: The management nuances of skull base meningiomas in the current era include optimal tumor control and maximal preservation of neurological status. Consequently, gamma knife (GK) radiosurgery has emerged as a popular alternative. Literature on maximum duration after which follow-up can be safely weaned is lacking. This study evaluates the temporal patterns of recurrence of skull base meningioma after secondary GK, either used as an adjuvant to microsurgery for residual lesions (Group A) or for treating recurrent lesions following surgical resection (Group B).

Methods: A total of 187 patients from 2000 to 2010 underwent microsurgical resection for skull base meningiomas by the senior author (AN). Further, 44 patients who underwent secondary GK (n = 25 in Group A, n = 19 in Group B) were retrospectively analyzed to determine their temporal recurrence.

Results: The majority of the patients were women (70%). The mean age was 55 years and the mean follow-up time after secondary GK was 51 months (range, 6–125 months). Radiological recurrence was noted in 20% of patients. Further six patients (24 %) in Group A and three patients (16 %) in Group B showed radiological recurrence. Kaplan-Meir charts were plotted to elucidate progression-free survival among Group A and Group B. The overall range of recurrence was 6 months to 123 months following secondary GK. Out of the nine recurrences, four recurred before 5 years, four recurred between 5 and 10 years, and one recurred after 10 years.

Conclusion: Although GK is considered to have optimal tumor control in treatment of skull base meningiomas, long-term follow-up beyond 10 years is suggested. It is still unclear what should be the ideal duration of follow-up, and further long-term prospective studies are needed to address this issue.