Effect of dural detachment on long-term tumor control for meningiomas treated using Simpson Grade IV resection

Abstract

Object Meningiomas treated by subtotal or partial resection are associated with significantly shorter recurrence-free survival than those treated by gross-total resection. The Simpson grading system classifies incomplete resections into a single category, namely Simpson Grade IV, with wide variations in the volume and location of residual tumors, making it complicated to evaluate the achievement of surgical goals and predict the prognosis of these tumors. Authors of the present study investigated the factors related to necessity of retreatment and tried to identify any surgical nuances achievable with the aid of modern neurosurgical techniques for meningiomas treated using Simpson Grade IV resection. Methods This retrospective analysis included patients with WHO Grade I meningiomas treated using Simpson Grade IV resection as the initial therapy at the University of Tokyo Hospital between January 1995 and April 2010. Retreatment was defined as reresection or stereotactic radiosurgery due to postoperative tumor growth. Results A total of 38 patients were included in this study. Regrowth of residual tumor was observed in 22 patients with a mean follow-up period of 6.1 years. Retreatment was performed for 20 of these 22 tumors with regrowth. Risk factors related to significantly shorter retreatment-free survival were age younger than 50 years (p = 0.006), postresection tumor volume of 4 cm3 or more (p = 0.016), no dural detachment (p = 0.001), and skull base location (p = 0.016). Multivariate analysis revealed that no dural detachment (hazard ratio [HR] 6.42, 95% CI 1.41–45.0; p = 0.02) and skull base location (HR 11.6, 95% CI 2.18–218; p = 0.002) were independent risk factors for the necessity of early retreatment, whereas postresection tumor volume of 4 cm3 or more was not a statistically significant risk factor. Conclusions Compared with Simpson Grade I, II, and III resections, Simpson Grade IV resection includes highly heterogeneous tumors in terms of resection rate and location of the residual mass. Despite the difficulty in analyzing such diverse data, these results draw attention to the favorable effect of dural detachment (instead of maximizing the resection rate) on long-term tumor control. Surgical strategy with an emphasis on detaching the tumor from the affected dura might be another important option in resection of high-risk meningiomas not amenable to gross-total resection.

A Novel Scoring System Based on Preoperative Routine Blood Test in Predicting Prognosis of Atypical Meningioma

“…In our study, tumor locating in skull base was confirmed as an independent risk factor for 3-year PFS in multivariate analysis. Fukushima et al reported that skull base location was independently associated with tumor recurrence in patients following Simpson Grade IV resection (41). Another study also validated the higher recurrence rate of skull base tumor in a Grade I-V cohort (42).…”

Is Simpson Grade I Removal Necessary in All Cases of Spinal Meningioma? Assessment of Postoperative Recurrence during Long-Term Follow-up

“…However, mass removal and generous coagulation of the dural attachment are highly recommended even in Simpson grade IV resection, because dural detachment is important to prevent recurrence in cases of Simpson grade IV removal in patients with intracranial meningiomas. 12) …”

The Simpson grade: abandon the scale but preserve the message

“…Fukushima et al examined a series of grade IV meningiomas and showed that a volume of residual tumor > 4 cm 3 predicted recurrence on univariate analysis. 19 Materi et al posed a similar question and used postoperative volumetric MRI to examine patients with Simpson grade IV resections. 20 The authors reported that residual volume > 5 cm 3 was associated with increased growth rate.…”