Hypofractionated CyberKnife stereotactic radiosurgery for acoustic neuromas with and without association to neurofibromatosis Type 2

Object Stereotactically guided radiosurgery is one of the primary treatment modalities for patients with acoustic neuromas (vestibular schwannomas). The goal of radiosurgery is to arrest tumor growth while preserving neurological function. Patients with acoustic neuromas associated with neurofibromatosis Type 2 (NF2) represent a special challenge because of the risk of complete deafness. To better define the tumor control rate and long-term functional outcome, the authors reviewed their 10-year experience in treating these lesions. Methods Forty patients underwent stereotactic radiosurgery at the University of Pittsburgh, 35 of them for solitary tumors. The other five underwent staged procedures for bilateral lesions (10 tumors, 45 total). Thirteen patients (with 29% of tumors) had undergone a median of two prior resections. The mean tumor volume at radiosurgery was 4.8 ml and the mean tumor margin dose was 15 Gy (range 12–20 Gy). The overall tumor control rate was 98%. During the median follow-up period of 36 months, 16 (36%) tumors regressed, 28 (62%) remained unchanged, and one (2%) grew. In the 10 patients for whom more than 5 years of clinical and neuroimaging follow-up results were available (median 92 months), five tumors were smaller and five remained unchanged. Surgical resection was performed in three patients (7%) after radiosurgery; only one showed radiographic evidence of progression. Useful hearing (Gardner-Robertson Class I or II) was preserved in six (43%) of 14 patients and this rate improved to 67% after modifications made in 1992. Normal facial nerve function (House-Brackmann Grade 1) was preserved in 25 (81%) of 31 patients. Normal trigeminal nerve function was preserved in 34 (94%) of 36 patients. Conclusions Stereotactically guided radiosurgery is a safe and effective treatment for patients with acoustic tumors in the setting of NF2. The rate of hearing preservation may be better with radiosurgery than with other available techniques.

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Radiation-induced rhabdomyosarcoma of the brainstem in a patient with neurofibromatosis Type 2

Journal of Neurosurgery ◽

10.3171/2009.6.jns09105 ◽

2010 ◽

Vol 112 (1) ◽

pp. 81-87 ◽

Cited By ~ 29

Author(s):

Matthew L. Carlson ◽

Dusica Babovic-Vuksanovic ◽

Ludwine Messiaen ◽

Bernd W. Scheithauer ◽

Brian A. Neff ◽

...

Keyword(s):

Tumor Suppressor ◽

Stereotactic Radiosurgery ◽

Tumor Suppressor Gene ◽

Neurofibromatosis Type ◽

Suppressor Gene ◽

Neurofibromatosis Type 2 ◽

Benign Tumors ◽

Autosomal Dominant Disorder ◽

Peripheral Nerve Sheath Tumors

Neurofibromatosis Type 2 (NF2) is a rare autosomal dominant disorder characterized by the development of benign tumors of the peripheral nervous system and the CNS, including schwannomas, meningiomas, and ependymomas. The gene responsible for the development of NF2 acts as a tumor suppressor gene. Stereotactic radiotherapy (SRT) or single-fraction stereotactic radiosurgery has been increasingly used in the past decades to treat benign tumors in patients with NF2. These radiotherapy methods are less invasive and can be potentially used to treat multiple tumors in a single session. The risk of inducing malignancy is unclear. Few reports exist of malignant peripheral nerve sheath tumors, meningiomas, or ependymomas occurring after SRT or stereotactic radiosurgery in patients with NF2. The authors present the first documented case of rhabdomyosarcoma following SRT for multiple NF2-associated schwannomas. Compared with patients with sporadic tumors, NF2 patients having a germline tumor suppressor gene defect may be more prone to secondary malignancies after treatment involving radiation therapy.

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Acoustic Neuromas and Neurofibromatosis Type 2

Otology and Neurotology ◽

10.1055/b-0034-80552 ◽

2013 ◽

Keyword(s):

Neurofibromatosis Type ◽

Neurofibromatosis Type 2 ◽

Acoustic Neuromas

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STEREOTACTIC RADIOSURGERY FOR VESTIBULAR SCHWANNOMAS IN PATIENTS WITH NEUROFIBROMATOSIS TYPE 2

Neurosurgery ◽

10.1227/01.neu.0000255340.26027.53 ◽

2007 ◽

Vol 60 (3) ◽

pp. 460-470 ◽

Cited By ~ 102

Author(s):

David Mathieu ◽

Douglas Kondziolka ◽

John C. Flickinger ◽

Ajay Niranjan ◽

Richard Williamson ◽

...

Keyword(s):

Stereotactic Radiosurgery ◽

Tumor Volume ◽

Gamma Knife Radiosurgery ◽

Neurofibromatosis Type ◽

Hearing Preservation ◽

Neurofibromatosis Type 2 ◽

Vestibular Schwannomas ◽

Factors Affecting

Abstract OBJECTIVE Vestibular schwannomas present significant management challenges in patients with neurofibromatosis Type 2 (NF2). We evaluated the results of gamma knife radiosurgery for the management of these tumors, focusing on tumor response, hearing preservation, and other factors affecting outcomes. METHODS Stereotactic radiosurgery was performed to manage 74 schwannomas in 62 patients. Ipsilateral serviceable hearing was present in 35% of tumors before the procedure. The mean tumor volume was 5.7 cm3. The mean margin and maximum dose used were 14 and 27.5 Gy, respectively. Cox regression analyses were performed to identify factors affecting outcomes. RESULTS The median follow-up period was 53 months, and two patients were lost to follow-up. Actuarial local control rates at were 85, 81, and 81% at 5, 10, and 15 years, respectively. Tumor volume was significant as a predictor of local control. Since 1992, using current radiosurgery techniques (magnetic resonance imaging scan targeting and reduced margin dose to 14 Gy or less), the actuarial serviceable hearing preservation rate is 73% at 1 year, 59% at 2 years, and 48% at 5 years after radiosurgery. Facial neuropathy occurred in 8% of tumors, trigeminal neuropathy occurred in 4%, and vestibular dysfunction occurred in 4%. Radiation dose and tumor volume were predictive of development of new deficits. No radiosurgery-associated secondary tumors or atypical or malignant changes were noted. CONCLUSION Stereotactic radiosurgery is a safe and effective management modality for neurofibromatosis Type 2 vestibular schwannomas. Although results do not seem to be as good as for patients with sporadic unilateral tumors, gamma knife radiosurgery results seem favorable and indicate that radiosurgery should be strongly considered for primary tumor management in selected patients.

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Growth Rate Characteristics of Acoustic Neuromas Associated With Neurofibromatosis Type 2

The Laryngoscope ◽

10.1097/00005537-199606000-00007 ◽

1996 ◽

Vol 106 (6) ◽

pp. 694-699 ◽

Cited By ~ 37

Author(s):

Mona M. Abaza ◽

Erini Makariou ◽

Mark Armstrong ◽

Anil K. Lalwani

Keyword(s):

Growth Rate ◽

Neurofibromatosis Type ◽

Neurofibromatosis Type 2 ◽

Acoustic Neuromas

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Stereotactic Radiosurgery for Vestibular Schwannomas in Patients with Neurofibromatosis Type 2: An Analysis of Tumor Control, Complications, and Hearing Preservation Rates

Yearbook of Otolaryngology-Head and Neck Surgery ◽

10.1016/s1041-892x(08)79191-1 ◽

2008 ◽

Vol 2008 ◽

pp. 17-18 ◽

Cited By ~ 1

Author(s):

B.J. Balough

Keyword(s):

Stereotactic Radiosurgery ◽

Neurofibromatosis Type ◽

Hearing Preservation ◽

Neurofibromatosis Type 2 ◽

Vestibular Schwannomas ◽

Tumor Control

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NCOG-12. STEREOTACTIC RADIOSURGERY FOR VESTIBULAR SCHWANNOMAS IN NEUROFIBROMATOSIS TYPE 2 PATIENTS: A SYSTEMATIC REVIEW AND META-ANALYSIS

Neuro-Oncology ◽

10.1093/neuonc/noaa215.551 ◽

2020 ◽

Vol 22 (Supplement_2) ◽

pp. ii131-ii132

Author(s):

Umberto Tosi ◽

Omri Maayan ◽

Anjile An ◽

Miguel Lavieri ◽

Sergio Guadix ◽

...

Keyword(s):

Stereotactic Radiosurgery ◽

Cranial Nerve ◽

Neurofibromatosis Type ◽

Neurofibromatosis Type 2 ◽

Vestibular Schwannomas ◽

Tumor Control ◽

Surgical Removal ◽

Impaired Hearing ◽

Cranial Nerve Palsies

Abstract BACKGROUND One of the hallmarks of neurofibromatosis type 2 (NF2) is the presence of bilateral vestibular schwannomas (VSs) that result in progressive hearing loss and compression of nearby brainstem structures causing cranial nerve palsies. Treatment of these tumors remains challenging, as both surgical removal and expectant management can result in symptom progression. Stereotactic radiosurgery (SRS) has recently been investigated for the management of NF2-associated VSs; however, the role, promises, and pitfalls of this treatment modality remain unclear. METHODS Ovid MEDLINE, EMBASE, Web of Science, and Cochrane Reviews were searched for studies assessing SRS outcome in NF2-associated VSs only. Primary endpoints included tumor control, serviceable hearing, presence of tinnitus, and cranial nerve V and VII symptoms. RESULTS A total of 16 studies (589 patients harboring 750 tumors) was included in this analysis. Clinical tumor control was achieved in 88% of cases (95% CI: 80%-95%); salvage surgery was needed in 8% (95% CI: 4%-13%) of cases. Treatment resulted in a worsening of pre-treatment serviceable hearing (OR of 0.26, p < 0.01), in an increase of facial nerve impairment (OR of 1.62, p < 0.01), and showed a trend for increase trigeminal nerve impairment as well (OR of 1.42, p = 0.07). The incidence of vestibular symptoms and hydrocephalus requiring shunting could not be assessed since these measures were not reported consistently. CONCLUSIONS The treatment of NF2-associated VS continues to pose a challenge, as current SRS regimens result in impaired hearing and worse cranial nerve comorbidities, despite achieving high tumor control. It remains unclear if these findings have to be intended as treatment complications or, rather, continuous disease progression despite tumor control.

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