A comparison of World Health Organization tumor grades at recurrence in patients with non-skull base and skull base meningiomas.
ABSTRACT Despite a favorable outcome for most patients with WHO Grade I meningiomas, a subset of these patients will have recurrent or progressive disease that advances to a higher grade and requires increasingly aggressive therapy. The goal of this study was to identify clinical characteristics associated with the recurrence of benign meningiomas and their acceleration to atypical and malignant histological types.
Records of 216 patients with WHO Grade I, II, or III meningioma that were initially treated between 1965 and 2001 were retrospectively reviewed. Median follow-up was 7.2 years.
Patients with non-skull base cranial meningiomas (82 of 105 [78%]) were more likely to have undergone a gross-total resection than patients with skull base meningiomas (32 of 78 [41%]; p < 0.001). Consequently, patients with Grade I non-skull base cranial meningiomas had better 5-year recurrence-free survival (69%) than patients with Grade I skull base meningiomas (56%) or Grade II or III tumors at any site (50%; p = 0.005). Unexpectedly, patients with non-skull base tumors who experienced a recurrence (8 of 22 [36%]) were more likely than patients with skull base tumors (1 of 19 [5%]) to have a higher grade tumor at recurrence (p = 0.024). Furthermore, the median MIB-1 labeling index of Grade I non-skull base cranial meningiomas (2.60%) was significantly higher than that of Grade I skull base tumors (1.35%; p = 0.016).
Cranial meningiomas that occur outside of the skull base are more likely to have a higher MIB-1 labeling index and recur with a higher grade than those within the skull base, suggesting that non-skull base cranial tumors may have a more aggressive biology than skull base tumors.
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ABSTRACT: The primary purpose of this study was to evaluate the efficacy of gamma knife radiosurgery (GKRS) when used as a treatment modality for cavernous sinus or posterior fossa skull-base meningiomas (SBMs), with particular attention given to whether or not intentional partial resection followed by GKRS constitutes an appropriate combination treatment method for larger SBMs. Of the 101 SBM patients in this series, 38 were classified as having cavernous sinus meningiomas (CSMs), and 63 presented with posterior fossa meningiomas (PFMs). The patients with no history of prior surgery (19 CSMs, 57 PFMs) were treated according to a set protocol. Small to medium-sized SBMs were treated by GKRS only. To minimize the risk of functional deficits, larger tumors were treated with the combination of intentional partial resection followed by GKRS. Residual or recurrent tumors in patients who had undergone extirpations prior to GKRS (19 CSMs, 6 PFMs) are not eligible for this treatment method (due to the surgeries not being performed as part of a combination strategy designed to preserve neurological function as the first priority). The mean follow-up period was 51.9 months (range, 6-144 months). The overall tumor control rates were 95.5% in CSMs and 98.4% in PFMs. Nearly all tumors treated with GKRS alone were well controlled and the patients had no deficits. Furthermore, none of the patients who had undergone prior surgeries experienced new neurological deficits after GKRS. While new neurological deficits appeared far less often in those receiving the combination of partial resection with subsequent GKRS, extirpations tended to be associated with not only a higher incidence of new deficits but also a significant increase in the worsening of already-existing deficits. Our results indicate that GKRS is a safe and effective primary treatment for SBMs with small to moderate tumor volumes. We also found that larger SBMs compressing the optic pathway or brain stem can be effectively treated, minimizing any possible functional damage, by a combination of partial resection with subsequent GKRS.Progress in neurological surgery 02/2009; 22:96-111.
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ABSTRACT: To investigate the feasibility of using intensity modulated radiotherapy (IMRT) for complex-shaped benign meningiomas of the skull base and report clinical experience. Twenty patients with benign skull-base meningiomas WHO degrees I (histopathologically proven in 16/20) were treated with IMRT between June 1998 and August 1999. Each tumor was complex in shape and adherent to, or encompassed, organs at risk (cranial nerves, optic apparatus, and brainstem). All patients, immobilized in a customized head mask integrated into a stereotactic system, were planned on an inverse treatment planning system using 5 or 7 coplanar, equidistant beams and 5 intensity steps. Each treatment plan was verified extensively before treatment. Follow-up with MRI and clinical examination was performed at 6 and 18 weeks and every 6 months thereafter. Target volumes ranged from 27 to 278 cc (median: 108 cc). Mean dose in 32 fractions ranged between 55.8 and 58.2 Gy. At median follow-up of 36 months (range: 31-43 months), pre-existing neurologic symptoms improved in 12/20 (60%), remained stable in 7/20 (35%), and worsened in 1 (5%) patient. Radiographic follow-up revealed significant tumor shrinkage 6 weeks post-IMRT in 2 patients and partial remission in 3 more patients at 9-17 months; other tumor volumes remained stable. There was no radiation-induced peritumoral edema, increase in tumor size, or new onset of neurologic deficits. Transient acute treatment side effects included nausea and vomiting and single occurrences of conjunctivitis/increased tearing and serous tympanitis. IMRT in the treatment of central nervous system meningiomas is feasible and safe, offering highly conformal irradiation for complex-shaped skull-base tumors while sparing adjacent critical structures. If the tumor remissions seen here are found in the ongoing treatments, IMRT may be considered the treatment of choice for inoperable or subtotally resected meningiomas and for otherwise difficult-to-treat, complex-shaped tumors of the central nervous system adjacent to critical structures, with the potential of dose escalation for malignant tumors.International Journal of Radiation OncologyBiologyPhysics 03/2003; 55(2):362-72. · 4.52 Impact Factor
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ABSTRACT: Recent study series have reported that post-operative external beam radiation therapy and stereotactic radiosurgery with the linear accelerator or gamma knife improves long-term local control of subtotally resected or recurrent meningiomas. Analysis of treatment results in 100 consecutive patients with skull base meningiomas managed by one surgeon with a median follow-up of five years. Treatment principles included observation for asymptomatic tumors; surgery for progressive or symptomatic tumors unless surgery was medically contraindicated or refused by the patient; to make surgery as aggressive as possible but with the goal of preserving full function of the patient; and to use radiosurgery or conformal fractionated radiation therapy if residual tumor was demonstrated. Preoperative, postoperative, and observational data were prospectively accumulated and stored in a large database system. Median follow up was 5 years with a range from 2 to 10 years. The most frequent presenting symptoms were headache (45%) and changes in vision (29%). Cranial nerve deficits (49%) and cerebellar signs (24%) were the most common physical findings. Seventy-two patients had surgical resection. Of these, 93% had greater than 50% resection and 47% had radiographically complete resection. There were no perioperative deaths and there were five surgical complications for a rate of 7%. Complications included hemiparesis (2.8%), new cranial nerve palsy (2.8%), and indolent osteomyelitis (1.4%). Fifteen patients had observation only; none of who progressed. Thirteen patients had radiation only, primarily because of patient preference or medical contraindications to surgery in the setting of substantial symptoms. There were no complications of this therapy. With a median five-year follow-up, only one patient (1%) demonstrated tumor progression using the treatment paradigm outlined here. These results demonstrate that skull base meningiomas which require treatment can be managed with a combination of aggressive surgery and conformal radiation with an acceptable functional status in 99% of cases.Acta Neurochirurgica 02/2001; 143(6):555-62. · 1.55 Impact Factor