Treatment Outcomes of Incidental Intracranial Meningiomas: Results from the IMPACT Cohort

Background: Incidental findings such as meningioma are becoming increasingly prevalent. There is no consensus on the optimal management of these patients. The aim of this study was to examine the outcomes of patients diagnosed with an incidental meningioma who were treated with surgery or radiotherapy.

Methods: Single-center retrospective cohort study of adult patients diagnosed with an incidental intracranial meningioma (2007-2015). Outcomes recorded were postintervention morbidity, histopathologic diagnosis, and treatment response.

Results: Out of 441 patients, 44 underwent treatment. Median age at intervention was 56.1 years (interquartile range [IQR], 49.6-66.5); patients included 35 women and 9 men. The main indication for imaging was headache (25.9%). Median meningioma volume was 4.55 cm3 (IQR, 1.91-8.61), and the commonest location was convexity (47.7%). Six patients underwent surgery at initial diagnosis. Thirty-eight had intervention (34 with surgery and 4 with radiotherapy) after a median active monitoring duration of 24 months (IQR, 11.8-42.0). Indications for treatment were radiologic progression (n = 26), symptom development (n = 6), and patient preference (n = 12). Pathology revealed World Health Organization (WHO) grade 1 meningioma in 36 patients and WHO grade 2 in 4 patients. The risk of postoperative surgical and medical morbidity requiring treatment was 25%. Early and late moderate adverse events limiting activities of daily living occurred in 28.6% of patients treated with radiotherapy. Recurrence rate after surgery was 2.5%. All meningiomas regressed or remained radiologically stable after radiotherapy.

Conclusions: The morbidity after treatment of incidental intracranial meningioma is not negligible. Considering most operated tumors are WHO grade 1, treatment should be reserved for those manifesting symptoms or demonstrating substantial growth on radiologic surveillance.