SURG-42. FACTORS INFLUENCING TUMOR RECURRENCE AFTER RESECTION OF SKULL-BASE MENINGIOMAS

Abstract

Abstract BACKGROUND Resection of skull-base meningiomas is challenging, given the proximity of and adherence to neurovascular structures. We characterize the benefits of neurosurgical resection of meningiomas, comparing clinical and surgical outcomes based upon tumor location within and outside the skull base. METHODS Data were retrospectively collected from 85 patients who underwent surgical resection of meningioma between 2008 – 2018, for whom long-term follow-up was available. Outcomes were compared between locations: non-skull base, anterior fossa, middle fossa, and posterior fossa. Logistic regression analysis was used to analyze pre-operative and pathologic factors influencing recurrence. RESULTS Forty-five (54.1%) tumors were located on the skull base: 29 anterior fossa, 22 middle, and 6 posterior. Simpson grade 1 or 2 resection was achieved in 63 patients. Mean Ki-67 showed a statically significant difference between all tumor locations: non-skull base (7.1), anterior fossa (4.0), middle fossa (10.8), posterior fossa (2.8) (p = 0.009). Simpson grade differed significantly by tumor location with percentage of Simpson grade 1 resections as follows: non-skull base supratentorial (45.7%), non-skull base infratentorial (0.0%), anterior (71.5%), middle (30.0%), posterior (16.7%) (p = 0.022). Tumors recurred in 11 patients with recurrence differing significantly between locations: non-skull base (18.2%), anterior (3.8%), middle (36.4%), posterior (0.0%) (p = 0.046). Median progression-free survival was 115.5 months and did not significantly differ by location. Larger tumor volumes (p = 0.018), Simpson grade 3 resection (p = 0.016), and increased Ki67 (p = 0.046) were associated with higher recurrence risk. No variables predicted post-operative neurological deficits. CONCLUSIONS High variability exists within skull-base meningiomas, depending on the cranial fossa of origin. Location may impact the molecular make-up, extent of resection, and patient outcomes. Due to the high-risk anatomy of the skull base, confirming these predictors of recurrence is vital to optimize initial treatment and decrease the risk associated with salvage treatment.