Incidental intracranial meningiomas: a systematic review and meta-analysis of prognostic factors and outcomes

Abstract

Background Incidental discovery accounts for 30% of newly-diagnosed intracranial meningiomas. There is no consensus on their optimal management. This review aimed to evaluate the outcomes of different management strategies for these tumors. Methods Using established systematic review methods, six databases were scanned up to September 2017. Pooled event proportions were estimated using a random effects model. Meta-regression of prognostic factors was performed using individual patient data. Results Twenty studies (2130 patients) were included. Initial management strategies at diagnosis were: surgery (27.3%), stereotactic radiosurgery (22.0%) and active monitoring (50.7%) with a weighted mean follow-up of 49.5 months (SD = 29.3). The definition of meningioma growth and monitoring regimens varied widely impeding relevant meta-analysis. The pooled risk of symptom development in patients actively monitored was 8.1% (95% CI 2.7–16.1). Associated factors were peritumoral edema (OR 8.72 [95% CI 0.35–14.90]) and meningioma diameter ≥ 3 cm (OR 34.90 [95% CI 5.17–160.40]). The pooled proportion of intervention after a duration of active monitoring was 24.8% (95% CI 7.5–48.0). Weighted mean time-to-intervention was 24.8 months (SD = 18.2). The pooled risks of morbidity following surgery and radiosurgery, accounting for cross-over, were 11.8% (95% CI 3.7–23.5) and 32.0% (95% CI 10.6–70.5) respectively. The pooled proportion of operated meningioma being WHO grade I was 94.0% (95% CI 88.2–97.9). Conclusion The management of incidental meningioma varies widely. Most patients who clinically or radiologically progressed did so within 5 years of diagnosis. Intervention at diagnosis may lead to unnecessary overtreatment. Prospective data is needed to develop a risk calculator to better inform management strategies. Electronic supplementary material The online version of this article (10.1007/s11060-019-03104-3) contains supplementary material, which is available to authorized users.

Indications and outcome in surgically treated asymptomatic meningiomas: a single-center case-control study

“…This finding corroborates a recently published Swedish registry-based study where a difference in waiting times was noted [3]. In the literature, the waiting time from diagnosis to intervention for asymptomatic meningiomas range from 7.3 to 48.8 months [3,7,9].…”

“…Histopathological grading often shows WHO grade I or II meningioma, but in our series, we found one anaplastic meningioma of WHO grade III. This has previously been reported in the literature, and the review by Islim et al [7] presents that 3 out of 316 (0.95%) patients had a grade III meningioma. Hence, anaplastic meningiomas are very rare among asymptomatic meningiomas but still sometimes seen.…”

“…Radiological progression, development of symptoms, and patient preference have been reported as indications for treatment for incidental meningiomas [7]. In line with the reports of a 5-year active monitoring period, a recent review found that intervention was carried out within 5 years of diagnosis in 94.3% of initially asymptomatic meningiomas [7]. Hence, if radiological progression should be a reason for intervention, at least 75% of patients with initial active monitoring would eventually be candidates for surgery.…”

Natural History of Meningiomas: Review with Meta-analyses

“…The rate of sympP in asymptomatic meningiomas was difficult to define from previous studies. In their review, Islim et al 34) described that 66 out of 608 patients with an incidental meningioma developed symptoms during the mean follow-up of about 40 months; this incidence is higher than our result (4.7%; 46 of 989 patients, mean followup of 53 months). This difference is considered to be due to the different inclusion criteria.…”

“…We could not analyze radiological factors in forest plots because few studies assessed their relationships and each study included only a small number of patients with symptom development. Although Islim et al 34) presented radiological factors in their forest plots (online resource 6), raw data were not provided in the original papers. 12,22,27) Analyses of individual data showed that maleness (P <0.0001) and initial volume (median 2.55 vs. 9.96 cm 3 ; P = 0.0032) or initial diameter (median 1.86 vs. 2.67 cm; P = 0.0035), but not age (P = 0.091), were related to sympP (Table 4).…”