Management of Recurrences of Non-Skull Base Meningiomas

Meningiomas are the most common intracranial extra-axial tumors. While the published literature is abundant regarding their primary management, fewer reports describe the proper clinical conduct for meningioma recurrences. In this context, surgery is considered the therapeutic strategy yielding the most effective results for recurrent meningiomas in terms of prolonged time to recurrence (TTR), progression-free survival (PFS), and overall survival (OS). When surgical indication is posed, some considerations must be taken into account. For instance, complex anatomical locations, such as the skull base, may preferably require radiosurgical treatments due to the remarkable risk of surgical complications. Similarly, patients in the elderly, in poor general conditions, or treated surgically multiple times may be candidates for radiation therapy (RT) or systemic treatments rather than surgery. The role of adjuvant RT to lower the risk of recurrence represents another thorny issue. With this regard, there is evidence that may suggest its efficacy for higher-grade meningiomas (II-III WHO grade). Nevertheless, whether adjuvant RT truly decreases tumor recurrence after gross total resection (GTR) of grade II meningiomas or not remains a matter of debate. Furthermore, albeit potentially effective in reducing the risk of recurrence, RT may increase the risk of chronic radiation side effects. Several systemic treatments have been explored to treat recurrent meningiomas. Although standard chemotherapy remains the only class of treatments for which some marginal benefit has been obtained, many efforts have been made to explore new therapeutic frontiers. In this context, target therapy and immunotherapy have shown modest results and, therefore, larger randomized clinical trials are necessary to shed light on this topic. In conclusion, surgical treatment should be regarded as the standard of care for recurrent non-skull base meningiomas. When specific risk factors, such as complex anatomical locations, poor general conditions, and the elderly are present, then RT and systemic treatments should be considered as salvage solutions.