Elsevier

World Neurosurgery

Volume 99, March 2017, Pages 104-110
World Neurosurgery

Original Article
Significance of the Extent of Resection in Modern Neurosurgical Practice of World Health Organization Grade I Meningiomas

https://doi.org/10.1016/j.wneu.2016.11.034Get rights and content

Objective

Since the prognostic importance of radical resection was introduced in 1957, the neurosurgery practice has undergone several technologic advancements. The aim of this study was to evaluate whether the prognostic value of the extent of resection is still relevant in modern neurosurgical practice.

Methods

Over a 10-year period, all patients with histologic-confirmed World Health Organization grade I meningiomas and who underwent meningioma surgery were retrospectively analyzed. Survival analyses were performed using Kaplan-Meier analysis and univariate and multivariate Cox proportional-hazards regression analyses.

Results

There were 113 patients included in this study. A better Simpson grade was associated with recurrence-free survival (RFS) 5, 10, and 15 years after surgery (P < 0.001). Comparing Simpson grade I with Simpson grades III and IV, 13.1 and 36.6 times higher hazard ratios were revealed with respect to RFS, respectively. A 7.5 times higher hazard ratio was revealed when comparing Simpson grades II and IV. Additional survival analyses were performed within specific locations and groups with low and high mitotic indices, demonstrating that the extent of resection can add additional information about RFS.

Conclusions

Simpson grade remains a highly significant predictor of RFS in meningioma-resected patients in modern neurosurgical practice. Extent of resection should therefore be emphasized when predicting prognosis and considering postoperative treatment and frequency of radiologic follow-up after surgery.

Introduction

In 1957, Simpson demonstrated that the recurrence rate after meningioma resection was associated with the extent of resection classified into 5 grades, today known as Simpson grades I–V.1 Since then, neurosurgeons all over the world have tried to achieve as radical removal of the tumor as possible, considering this the optimal cure for these patients.2, 3, 4

In the last 60 years, meningioma surgery has undergone numerous innovations,5, 6 comprising resection techniques, instrumentation, and introduction of operative microscope and microsurgical techniques.5 Furthermore, improvements have been made in magnetic resonance imaging techniques, facilitating image-guided technology and detection of recurrent meningiomas. In addition, advancements have been made in the field of radiosurgery and radiation therapy, constituting additional and alternative treatments for patients suffering from these tumors. Considering the advancements in modern meningioma surgery, the rate of successful operations has dramatically increased in the last decades.7 The prognostic value of Simpson grade may therefore have changed, and it is reasonable to question the relevance of this grading in modern neurosurgical practice.

Despite all the innovations in modern neurosurgical practice, only a few studies have attempted to validate the extent of resection as a predictor of patient outcome within the last 20 years. Sughrue et al.5 could not prove any significant difference between any of the Simpson resection grades in terms of recurrence-free survival (RFS). This observation indicates no prognostic benefit of complete resection of tumors with the dural attachment and underlying bone, compared with simply removing the entire tumor, or even leaving small amounts. In agreement with Sughrue et al.,5 Oya et al.8 found no significant difference between Simpson grade I–, II–, and III–resected patients in terms of recurrence. Similarly, Hasseleid et al.9 suggested no significant difference in retreatment-free survival for patients who underwent resections corresponding to Simpson grades II, III, IV, and V. Consequently, the relevance of Simpson grade in modern neurosurgical practice, and the benefits of achieving a more radical resection, has been brought into question.

To determine whether a more radical resection of World Health Organization (WHO) grade I meningiomas may be more detrimental than beneficial in modern neurosurgery practice, the aim of this study was to compare the RFS associated with different extents of resection according to the guidelines of the Simpson grade.

Section snippets

Patient Population

Over a 10-year period between January 1, 1991, and December 31, 2000, all patients with histologic-confirmed WHO grade I meningioma who underwent meningioma surgery at St. Olavs Hospital, Trondheim University Hospital were retrospectively analyzed. Patients under the age of 18 years, with nonintracranial meningiomas, or who received radiation immediately after surgery were excluded.

Clinical Data

All medical records, including neurosurgery, radiology, and pathology reports, were obtained. Collected data

Clinical Data

A summary of the clinicopathologic data according to Simpson grade is presented in Table 2. There were 113 patients who met the inclusion criteria. The median age for all patients was 58 years, ranging from 27 to 84 years. Eighty-nine (78.8%) women and 24 (21.2%) men were included (female/male ratio, 3.7:1). According to the guidelines of Simpson grade, 35 (31.0%) cases were classified as grade I, 48 (42.5%) as grade II, 16 (14.2%) as grade III, and 14 (12.4%) as grade IV. The RFS rates within

Discussion

Since prognostic importance of radical resection was introduced in 1957, the neurosurgery practice has undergone several technological advancements. However, only a few studies have attempted to validate the extent of resection as a predictor of patient outcome within the last 20 years. Of these, little or negligible benefits have been described in the most radical surgeries with complete removal of the tumor with the affected dural attachment and underlying bone, compared with simply removing

Conclusions

Simpson grade remains a highly significant predictor of RFS in meningioma-resected patients in modern neurosurgical practice, independent of other clinical factors. Furthermore, this study demonstrates that the extent of resection adds additional information about RFS within patients stratified by mitotic index and tumor location. The extent of resection should therefore be highly emphasized when predicting prognosis and considering postoperative treatment and frequency of radiologic follow-up

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Conflict of interest statement: The authors declare that the article content was composed in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

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