Necrosis in a meningioma following systemic chemotherapy. Case report

Treatment of meningioma: an update

Aggressive surgical resection continues to be the mainstay of current meningioma management, with advances in microsurgical techniques facilitating the safety and effectiveness of this approach. Complete surgical removal of meningiomas provides the optimal opportunity for long-term remission. Advances in skull base surgical approaches have greatly improved patient outcomes for tumors in precarious locations once thought to be inoperable. For tumors that recur or are unresectable, stereotactic radiosurgery and conformal fractionated radiation therapy can provide safe, palliative treatment with favorable long-term outcomes. Additionally, advances in the understanding of molecular biologic and biochemical mechanisms underlying meningioma growth offer unique opportunities for potential treatment adjuncts for atypical and malignant tumors. This review discusses current understanding of meningioma pathology and accepted meningioma treatment paradigms. The technologic advances and experimental strategies for the future treatment of complex intracranial meningiomas are also discussed.

Stabilization of disease progression by hydroxyurea in patients with recurrent or unresectable meningioma

OBJECT

The management of certain meningiomas of the skull base and those involving the dural venous sinuses remains a challenge. In recent reports it has been suggested that hydroxyurea chemotherapy can cause regression of unresectable and recurrent meningiomas. The authors report their experience in using hydroxyurea for the treatment of patients with recurrent or unresectable meningiomas.

METHODS

Hydroxyurea was administered at a dosage of approximately 20 mg/kg/day to 11 women and nine men (median age 59 years, range 31-75 years) with recurrent or unresectable intracranial meningiomas (12 basal, two parasagittal, and six multiple). In 16 patients the meningiomas were benign, in three they had atypical features, and in one the meningioma was malignant. All patients had measurable residual disease. Four patients with benign meningiomas had previously received radiotherapy (two were treated with conventional fractionated radiotherapy and two with stereotactic radiosurgery), three with atypical meningiomas received conventional fractionated radiotherapy, and the one with a malignant meningioma received conventional radiotherapy with additional stereotactic radiosurgery. Tumor enlargement was documented in all patients on neuroimages obtained before initiation of hydroxyurea therapy. All patients were evaluable for response to therapy. In 12 patients with benign meningiomas, the disease had stabilized on neuroimages obtained posttreatment (median duration of treatment 122 weeks, range 8-151 weeks), and two of these showed clinical improvement. One patient with a benign meningioma experienced a minor partial response that was noted after 39 weeks of treatment and was confirmed on neuroimaging and clinical evaluations. In three others with benign meningiomas, progression was confirmed on neuroimages obtained after 41, 55, and 66 weeks, respectively: the 1-year freedom from progression rate was 0.93 (standard error 0.07) in patients with benign meningiomas. In three patients with atypical meningiomas, the tumors had progressed on neuroimages obtained after 12, 19, and 45 weeks, respectively. In the patient with a malignant meningioma, progression was confirmed on neuroimages obtained at 24 weeks. Hydroxyurea has been reasonably well tolerated, although one patient discontinued therapy because of moderate myelosuppression.

CONCLUSIONS

Although tumor regression appears uncommon, these results indicate that hydroxyurea may arrest progression of unresectable or recurrent benign meningiomas.

Regression of a presumed meningioma with the antiestrogen agent mepitiostane. Case report

This 68-year-old woman underwent a distal gastrectomy for gastric cancer in August 1994. A presumed meningioma of the falx was found incidentally on a staging examination of the gastric cancer, but the meningioma was not treated with surgery. Instead, after gastrectomy the patient received tegafur as adjuvant chemotherapy until February 1996, when she was readmitted to the hospital because of loss of appetite and emaciation but with no recurrence of the gastric cancer. A computerized tomography scan obtained during this second admission showed no change in the meningioma. To improve her general condition, tegafur was discontinued and she was started on a course of the antiestrogen agent mepitiostane. Administration of mepitiostane for approximately 2 years resulted in a marked regression (73%) of the meningioma. This is the first reported case of a presumed meningioma that regressed as a result of use of the antiestrogen agent mepitiostane.

Hydroxyurea for treatment of unresectable and recurrent meningiomas. II. Decrease in the size of meningiomas in patients treated with hydroxyurea

In this paper the authors present the first evidence that meningiomas respond to treatment with hydroxyurea. Hydroxyurea was administered as an adjunct chemotherapeutic treatment in patients with recurrent and unresectable meningiomas. Hydroxyurea was used because experimental data demonstrated that it inhibits growth of cultured human meningioma cells and meningioma transplants in nude mice by inducing apoptosis. The authors therefore treated four selected patients with hydroxyurea. All patients had undergone multiple gross resections and all except one received radiotherapy. Three patients with recurrent Grade I meningiomas assessed according to World Health Organization (WHO) guidelines received hydroxyurea because of an increased tumor growth rate, documented by magnetic resonance (MR) imaging, within a 6- or 12-month interval. A fourth patient with a malignant meningioma (WHO Grade III) began a course of treatment with hydroxyurea immediately after his sixth palliative operation without waiting for another relapse to be demonstrated on MR imaging. Because of their location and invasive growth behavior none of the meningiomas could have been removed completely by surgical intervention. All patients received hydroxyurea at a dosage level of 1000 to 1500 mg/day (approximately 20 mg/kg/day). In a man with a large sphenoid wing meningioma invading the right cavernous sinus and the temporal base, the intracranial tumor mass was reduced by 60% during 6 months of treatment. A woman with a large ball-shaped meningioma of the right sphenoid wing invading the cavernous sinus exhibited a 74% decrease of the initial tumor volume in 10 months of treatment with oral hydroxyurea. Serial MR images obtained monthly revealed that the process of size reduction was continuous and proportionate. The shrinkage of the tumor was accompanied by a complete remission of symptomatic trigeminal neuralgia after 2 months and by improved abducent paresis after 5 months. The third patient had a slowly growing meningioma that exhibited a 15% reduction in mass when reassessed after 5 months of hydroxyurea treatment. The fourth patient with the malignant meningioma in the left cerebellopontine angle has had no recurrence for 24 months. Long-term treatment with hydroxyurea may result in full remission of tumors in meningioma patients. The preliminary data indicate that hydroxyurea provides true medical treatment in patients with unresectable and recurrent meningiomas, replacing palliative surgery and radiotherapy in the management of this disease.

Gamma knife radiosurgery as a lesioning technique in movement disorder surgery

Fifty-five patients underwent radiosurgical placement of lesions either in the thalamus (27 patients) or globus pallidus (28 patients) for treatment of movement disorders. Patients were evaluated pre- and postoperatively by a team of observers skilled in the assessment of gait and movement disorders who were blinded to the procedure performed. They were not associated with the surgical team and concomitantly and blindly also assessed a group of 11 control patients with Parkinson's disease who did not undergo any surgical procedures. All stereotactic lesions were made with the Leksell gamma unit using the 4-mm secondary collimator helmet and a single isocenter with dose maximums from 120 to 160 Gy. Clinical follow-up evaluation indicated that 88% of patients who underwent thalamotomy became tremor free or nearly tremor free. Statistically significant improvements in performance were noted in the independent assessments of Unified Parkinson's Disease Rating Scale (UPDRS) scores in the patients undergoing thalamotomy. Eighty-five and seven-tenths percent of patients undergoing pallidotomy who had exhibited levodopa-induced dyskinesias had total or near-total relief of that symptom. Clinical assessment indicated improvement of bradykinesia and rigidity in 64.3% of patients who underwent pallidotomy. Independent blinded assessments did not reveal statistically significant improvements in Hoehn and Yahr scores or UPDRS scores. On the other hand, 64.7% of patients showed improvements in subscores of the UPDRS, including activities of daily living (58%), total contralateral score (58%), and contralateral motor scores (47%). Ipsilateral total UPDRS and ipsilateral motor scores were both improved in 59% of patients. One (1.8%) of 55 patients experienced a homonymous hemianopsia 9 months after pallidotomy due to an unexpectedly large lesion. No other complications of any kind were seen. Follow-up neuroimaging confirmed correct lesion location in all patients, with a mean maximum deviation from the planned target of 1 mm in the vertical axis. Measurements of lesions at regular interals on postoperative magnetic resonance images demonstrated considerable variability in lesion volumes. The safety and efficacy of functional lesions made with the gamma knife appear to be similar to those made with the assistance of electrophysiological guidance with open functional stereotactic procedures. Functional lesions may be made safely and accurately using gamma knife radiosurgical techniques. The efficacy is equivalent to that reported for open techniques that use radiofrequency lesioning methods with electrophysiological guidance. Complications are very infrequent with the radiosurgical method. The use of functional radiosurgical lesioning to treat movement disorders is particularly attractive in older patients and those with major systemic diseases or coagulopathies; its use in the general movement disorder population seems reasonable as well.

Chemotherapy for meningiomas

The most efficacious treatment for meningiomas is surgery. For incompletely resected or recurrent tumors, radiotherapy can be given. However, when the meningioma is unresectable and/or all other previous treatments have failed, immunotherapy or chemotherapy may be considered for malignant tumors and immunotherapy and hormone therapy may be considered for benign ones. Various chemotherapy treatments that have shown some efficacy in individual cases include combinations of Adriamycin and Dacarbazine or Ifosfamide and Mesna. The most effective immunotherapy appears to be administration of interferon-alpha, which is relatively non-toxic and easily tolerated. However, more studies are needed to better define the roles of these agents in the management of a recurrent, unresectable, or malignant meningiomas.