Does Prior Microsurgery Improve or Worsen Stereotactic Radiosurgery Outcome for Cavernous Sinus Meningiomas?
Cavernous sinus meningiomas are increasingly treated with stereotactic radiosurgery alone or combined with surgical resection of tumor external to the cavernous sinus. From the University of Pittsburgh, Kano et al reported one of the largest series of cavernous sinus meningiomas treated with stereotactic radiosurgery: 272 patients underwent gamma knife stereotactic radiosurgery (SRS) for cavernous sinus meningiomas over 23 years, with 99 having prior microsurgical resection. Median marginal dose was 13 Gy and median follow-up was 62 months (range 6-209 months). Post-SRS improvement of pre-existing cranial nerve symptoms was observed in 37% (54 of 145) of patients who did not have prior microsurgery. Only 14% of patients who had prior microsurgery showed improvement in pre-existing cranial nerve symptoms after SRS (p = .001). The incidence of new cranial nerve deficits (11% overall) after SRS and progression-free survival (94% at 5 years, 86% at 10 years) were comparable between the two groups. Therefore for large cavernous sinus meningiomas, the authors strongly recommend a multi-stage strategy of initial tumor resection for the tumor outside the cavernous sinus followed by SRS for tumor within the cavernous sinus.