Cavernous sinus metastases treated with gamma knife™ stereotactic radiosurgery
Amit Ayer, Brandi R. Page, John T. Lucas Jr., J. Daniel Bourland, Eric R. Oliver, Stephen B. Tatter, Thomas L. Ellis and Michael D. Chan
Background: Cavernous sinus metastases represent difficult clinical scenarios because of the lack of surgical options. We investigate the use of Gamma Knife stereotactic radiosurgery (GKRS) as a treatment option of these metastases.
Objectives: To determine the patterns of failure for cavernous sinus metastases and to identify factors that predict for improved outcomes.
Methods: This is a retrospective review of 19 patients treated with GKRS for cavernous sinus metastases over a 9-year period between May 2002 and October 2011. The median marginal tumor dose was 18 Gy. Patients were followed with serial imaging. Kaplan Meier analysis was used to estimate local control and overall survival. Fischer exact test was used to determine any predictive factors for local control or survival.
Results: Median follow-up time was 22.4 months. Kaplan Meier estimate of overall survival at 1, 2, and 4 years was 76%, 44%, and 44% survival, respectively. 11 patients experienced intracranial failure. Of these, 7 (64%) were local and 4 (36%) were distant intracranial failures. Local control was 76%, 44%, and 44% at 1, 2 and 4 years, respectively. Six of seven local failures in the series were considered to be marginal failures because they were abutting the 50% isodose volume. Head and neck primary tumors were associated with 86% of local failures (P = 0.017) and was the only factor that predicted for local failure.
Conclusions: GKRS appears to be a feasible and safe modality for treatment of cavernous sinus metastases. Local failures appear to be due to a marginal miss of microscopically occult disease.
Keywords: Cavernous sinus, metastases, Gamma Knife, radiosurgery, stereotactic radiosurgery