Radiotherapy for atypical meningiomas

Abstract

The authors have performed the largest study in the literature to examine the use of radiotherapy for WHO Grade II, atypical, meningiomas following a first-time resection. They suggest that radiotherapy is not appropriate after first-time resection of those lesions in which a gross-total resection (Simpson Grade 1 or 2) has been achieved. They also advise that any tumor remnant radiologically demonstrated on postoperative imaging should be treated with radiosurgery and that postoperative radiotherapy after a first-time resection should be reserved for tumor remnants too large for radiosurgery and for which a second staged operation is not planned.

An evidence-based treatment algorithm for the management of WHO Grade II and III meningiomas

“…2,3,45 These studies reported improved LC or a trend toward improved LC with adjuvant EBRT and GTR versus GTR alone (p = 0.04, p = 0.09, and p = 0.10; tine adjuvant EBRT after GTR (Table 3). 13,24,26,37,46,48,59,78,81,85 Eight of these 10 studies did not detect any significant improvement in PFS with adjuvant EBRT, and the remaining 2 studies did not detect any significant improvement in LC. The discrepancy between these and the aforementioned 3 studies may in part be due to the categorization of less intrinsically aggressive or more radiation-resistant meningiomas as 2000/2007 WHO AMs compared with the 1993 WHO criteria.…”

“…46 Studies supporting adjuvant EBRT may be reporting on more aggressive AMs, which could account for their high recurrence rates after GTR (27%-32%) and the trends toward improved LC with adjuvant EBRT. Interestingly, studies have shown that after controlling for EOR, a skull base location does not correlate with recurrence in AMs (8 of 8 studies), 24,37,46,48,57,77,78,85 and therefore should not necessarily trigger a recommendation of adjuvant EBRT after GTR.…”

“…The 5-year PFS after GTR is 59%-90% but the 5-year PFS after subtotal resection (STR) is only 30%-70% (Table 2). 13,24,26,46,48,59,77,78,81,85,87 For each of these studies, GTR shows a significant benefit over STR or Simpson Grade IV resection for AMs (EBM Level 3, Grade 1C recommendation). However, "maximal safe resection" may be a more appropriate strategy than GTR, given the surgical morbidity associated with resection in certain locations (e.g., cavernous sinus).…”

“…Five of 8 studies using 2000/2007 WHO guidelines demonstrated improved PFS after adjuvant EBRT (Table 4). 24,26,37,46,48,59,77,81 However, Grade II meningiomas represent a heterogeneous group of tumors, 47,51,53 and not all patients may benefit equally from adjuvant EBRT. 24,26,77,85 In particular, histological necrosis has been shown to be a strong predictor of radioresistance in a large study by Sun et al, 77 such that the efficacy of adjuvant EBRT may be limited in AMs with necrosis (EBM Level 3, Grade 2C recommendation).…”

Primary Extracranial Meningioma of the Sphenoid Sinus: A Hidden Menace

“…Recurrence is very rare following adequate surgical resection. 10 Most meningiomas are benign with no tendency to metastasize and malignant change is rare. In general, the prognosis of primary meningioma of the sinonasal tract appears to be excellent.…”