Recurrence and regrowth of benign meningiomas

Abstract

The World Health Organization (WHO) grading system for meningioma is helpful for predicting aggressive subtypes. However, even benign meningiomas sometimes show relatively rapid growth and may recur after total removal. We attempted to find histopathological features that would be valuable for predicting recurrence or regrowth of WHO grade I meningiomas. We investigated 135 benign meningiomas, of which 120 were totally removed (Simpson's grade I-III). The median follow-up period was 9.7 years (1-21 years). The recurrence rate in the patients with total removal was 7.5% at 10 years and 9.3% at 20 years. The univariate analysis revealed that MIB-1 index (>or=2%), existence of mitosis, absence of calcification, and paucity of fibrosis significantly correlated with recurrence. On the other hand, the histological features of sheet-like growth, prominent nucleoli, and necrosis did not correlate with recurrence, because they were relatively rare in grade I tumors. Multivariate analysis revealed that high MIB-1 index and absence of calcification significantly correlated with recurrence. The patients with recurrent or residual tumors did not always receive adjuvant treatment. Including subtotally treated tumors, the retreatment rate was 9.8% at 10 years and 25.6% at 20 years. MIB-1 index and Simpson's grade significantly correlated with retreatment in both univariate and multivariate analyses.

Radiological Predictive Factors for Regrowth of Residual Benign Meningiomas

“…The incidence of recurrence after total resection or residual tumor growth is reportedly 7-25%, even in tumors considered benign meningioma (grade I). 24) Therefore, the clinical course of benign meningioma is not necessarily favorable, 30) and many studies have investigated the prediction of postoperative recurrence, 16,18,22) particularly after total resection, usually based on the clinical or imaging findings of patients, but recently mainly based on the tumor growth potential, that is MIB-1 index. 14,15,17,18,31,32,34) MIB-1 index can be used as an index within a facility, but general comparison is difficult because no standard measurement method has been established, and the value markedly varies depending on the measurement site within a preparation.…”

“…24) Therefore, the clinical course of benign meningioma is not necessarily favorable, 30) and many studies have investigated the prediction of postoperative recurrence, 16,18,22) particularly after total resection, usually based on the clinical or imaging findings of patients, but recently mainly based on the tumor growth potential, that is MIB-1 index. 14,15,17,18,31,32,34) MIB-1 index can be used as an index within a facility, but general comparison is difficult because no standard measurement method has been established, and the value markedly varies depending on the measurement site within a preparation. 18,19) Subsequently, the MIB-1 index considered to predict a high risk of recurrence or regrowth varies from 2% to 5%, 15,17,18,31) but the WHO classification considers that the mean MIB-1 index of grade I benign meningioma is generally 3.8%, showing the problem as a general predictor of regrowth in global criteria.…”

“…14,15,17,18,31,32,34) MIB-1 index can be used as an index within a facility, but general comparison is difficult because no standard measurement method has been established, and the value markedly varies depending on the measurement site within a preparation. 18,19) Subsequently, the MIB-1 index considered to predict a high risk of recurrence or regrowth varies from 2% to 5%, 15,17,18,31) but the WHO classification considers that the mean MIB-1 index of grade I benign meningioma is generally 3.8%, showing the problem as a general predictor of regrowth in global criteria. The WHO classification does not define the grade of meningioma by MIB-1 index, so MIB-1 index is only used as a reference value under the present conditions.…”

“…The therapeutic strategy for residual tumors or the course after total resection has recently been based on the MIB-1 index, as an indicator of the proliferative potential of tumors. 14,15,17,18,31,32,34) However, the MIB-1 index has various problems, 18,19) so may be used as a criterion within a facility, but is difficult to use as a global standard for evaluation.…”

Intracranial meningiomas: Two-years experience of Mustafa Kemal University

“…(a): MRI brain (gado) axial (plain) section shows anterior parasagittal falx meningioma (b): Post-operative CT shows totally removed remains elusive but female predominance suggests a role for hormonally mediated risk factors (Claus et al, 2012). Trauma, ionizing radiation, brain injury, smoking, chronic viral infection, chromosomal abnormalities are proposed to be other predisposing factors (Phillips et al, 2005;Nakasu et al, 2009). We could not demonstrate spesific etiological agents in our cases which could be related to the minority of our study group.…”