MANAGEMENT AND OUTCOMES OF INCIDENTAL MENINGIOMAS: IS ROUTINE FOLLOW-UP REQUIRED?

30% of newly-diagnosed meningiomas are incidental findings. There is no consensus on the optimal management of these patients. To determine the clinical outcomes of patients diagnosed with incidental meningioma. Single centre retrospective cohort study of patients diagnosed with an incidental meningioma between 2007 and 2015. 441 patients were included (459 meningiomas). Mean age at diagnosis was 63.3 years (range: 19–97); 348 female and 93 male. The main indication for MRI/CT was headache (25.9%). Median meningioma volume at diagnosis was 1.58 cm3 range: 0.06–51.8). Commonest location was convexity (39.9%). At initial presentation, 6 patients underwent surgical resection, 50 were discharged and the remaining 385 entered surveillance imaging (1303 scans in total, 3.4 on average over a median of 36 months [range: 3–120]). Overall outcomes by the end of the study period were: 219 discharged, 12 lost to follow-up, 4 deaths (unrelated to their meningiomas) and 206 under continued observation. Of those 206, 38 (18.4%) (mean age: 52.9 years) had intervention (34 surgery, 2 stereotactic radiosurgery, 2 fractionated radiotherapy) after a median follow-up period of 24 months (range: 3–78). Indications for treatment were radiological progression (n=26), development of symptoms (n=6), and patient preference (n=6). Pathology revealed WHO grade I (benign) in 36 patients and WHO grade II (atypical) in 4 patients, of which one had recurrence 5 months after surgery and required salvage radiotherapy. For 231 patients discharged/lost to follow-up (mean age: 68.1 years), median follow-up duration was 18 months (range: 0–120). Nine patients (3.9%) had further MRI/CT for unrelated symptoms after a median of 37 months. The majority of incidental meningiomas do not require long-term follow-up and our data suggests that a 5-year period is sufficient. Further analyses of clinical and radiological predictors of growth and subsequent intervention are planned.