Recurrence of Resected Skull Base Meningiomas during Long-term Follow-up: Incidence and Predisposing Factors.

Skull base meningiomas (SBMs) are often subtotally resected and there is a paucity of evidence regarding the long-term rates of postoperative tumor progression. We aimed to investigate the factors that influence tumor recurrence in patients with an extended period of follow-up.  Surgically resected tumors with long-term radiological follow-up were included for analysis. Data were collected on patient demographics, anatomical location, Simpson grade, World Health Organization (WHO) grade, modality of reintervention, and functional status. Recurrence was defined as tumor progression requiring intervention. Kaplan-Meier method and log-rank test were used to calculate recurrence-free probability. Cox regression analysis was used to determine factors associated with tumor progression.  Sixty-one patients were identified. Median radiological follow-up was 11.25 (IQR 4.3) years. Median age at first surgery was 50 (IQR 17) years. A total of 55/61(90%) tumors were WHO grade I and 6/61(10%) were grade II. Gross total resection (GTR) was achieved in 37/61 (60.7%) patients with subtotal resection (STR) in 24/61 (39.3%). In total, 28/61(45.9%) demonstrated recurrence/regrowth with a median time to recurrence of 2.8 (IQR 5) years. Also, 15/37 (40.5%) and 13/24 (54.2%) patients with GTR and STR, respectively, had tumor recurrence. Of the 28 recurrences, 4/28 (14.3%) underwent reresection, 9/28 (32.1%) were managed with radiotherapy, and 15/28 (53.6%) received both reresection and radiotherapy. Tumor grade was the only significant predictor of tumor recurrence (  = 0.033). Neurological function at last follow-up was significantly worse (modified Rankin scale >2) in patients with recurrence (  = 0.035).  Surgically resected SBMs are associated with a significant recurrence rate during prolonged follow-up, irrespective of the extent of resection achieved. We recommend a prolonged period of radiological surveillance for SBM following surgical resection.