The role of adjuvant radiotherapy in atypical meningioma

Abstract

The object of this study was to analyze treatment outcomes and to identify the prognostic factors, with a focus on the role of adjuvant radiotherapy (ART), predicting disease progression in atypical meningiomas. From 1997 to 2011, 83 patients with meningioma were included in this study. All patients were histologically confirmed as atypical meningioma and were treated with surgical resection with or without ART. As primary therapy, 27 patients received surgical resection followed by ART, and 56 received no adjuvant therapy. Of 83 evaluable patients, 55 (66.3 %) patients underwent complete resection. The median ART dose was 61.2 Gy and their median age was 52 years. The 5- and 10-year actuarial overall survival rates were 90.2 and 62.0 %, and the 5- and 10-year progression-free survival (PFS) rates were both 48.0 %, with a median follow-up of 43.0 months. Addition of ART (p = 0.016) and complete tumor resection (p = 0.002) were associated with superior PFS. When stratified to four groups according to resection status and ART, the groups of patient with incomplete resection without ART showed significantly worse PFS compared to other three groups (p < 0.001). In conclusion, surgical resection followed by ART led to lower local tumor progression in patients with atypical meningioma defined by the updated 2000/2007 WHO classification. Our results may contribute to the routine use of ART, especially after incomplete resection, until the outcomes of ongoing prospective trials are available.

Results of immunohistochemical staining for cell cycle regulators predict the recurrence of atypical meningiomas

“…Clinically, recurrence rates vary between studies, depending on both the duration of follow-up and the number of patients studied. An analysis of some of these studies has shown that the patient's age at diagnosis, 20 complete resection or GTR, 30 and postoperative radiotherapy 20,33 are invariably associated with lower risks of atypical meningioma recurrence.…”

EANO guidelines for the diagnosis and treatment of meningiomas

“…In a series of 83 patients of whom 66% had undergone GTR, Park et al reported a 5-year tumor control of 59% versus 44% with and without postoperative RT, respectively 72 . Improved progression-free survival rates after postoperative RT have been observed in comparative retrospective series [73][74][75] .…”

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.…”

“…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).…”