Introduction: Extracranial meningioma metastases are rare, and patients with meningiomas are not routinely screened for systemic metastases. In this series, we report our experience with meningioma metastases and our institutional experience screening for metastases in select patients with recurrent meningiomas.
Methods: All patients undergoing surgical resection or stereotactic radiosurgery for primary or recurrent meningioma from 2009 to 2017 at a single center were retrospectively reviewed. Indications for metastasis screening were patients with recurrent meningioma after 2 prior resections and radiation therapy or symptoms concerning for metastasis. Screening was performed with CT chest/abdomen/pelvis, FDG PET-CT, or somatostatin receptor specific (DOTATATE) PET-CT.
Results: Of 1203 patients treated, 929 (77.2%) had WHO grade 1 meningioma by surgical pathology or imaging, 234 (19.5%) had grade 2 and 35 (2.9%) had grade 3 meningioma. A total of 298 meningiomas (24.8%) recurred, with a mean of 1.6 recurrences per patient. Screening for metastases was performed in 28 patients; one (3.6%) had a grade 1 tumor, 16 (57.1%) were grade 2, and 11 (39.3%) were grade 3. Five patients (17.9%) were screened because of systemic symptoms. Of the patients screened, 27 (96.4%) had recurrent meningioma, with a mean 3.2 recurrences. Ten patients (35.7%) had suspicious extracranial lesions by imaging. On biopsy, 8 were meningioma metastases, 1 was a non-meningioma malignancy, and 1 was lost to follow-up. Biopsy-confirmed metastases occurred in: liver (5), lung (3), mediastinum (1) and bone (1). The overall incidence of metastases was 0.67% (n=8). Incidence increased to 2% of WHO grade II tumors and 8.6% of grade 3. Using our indications, the number needed to screen to identify one patient with biopsy-confirmed malignancy was 3.1.
Conclusions: Screening of patients with multiply recurrent meningioma or symptoms concerning for metastasis may identify extracranial metastases in a significant proportion of patients and can inform decision making for additional treatments.
Patient Care: The findings in our study will allow neurosurgeons and neuro-oncologists to identify meningioma patients at high risk for systemic metastases and be aware of the latest developments in somatostatin-specific, DODATATE-PET, whole body imaging for identifying metastatic meningiomas.
Learning Objectives: By the conclusion of this session, participants should be able to 1) Describe the overall incidence of metastases in meningioma, 2) Discuss the fact that in contrast to non-recurrent meningiomas, recurrent grade II and III meningiomas have a rather high rate of metastases, 3) Identify meningioma patients who should be screened for metastases and be aware of the utility of DODATATE-PET (somatostatin specific) in specifically diagnosing meningioma metastases.