Low Dose Stereotactic Radiosurgery for Vestibular Schwannomas: Tumor Control and Cranial Nerve Function Preservation After 11Gy

Abstract OBJECTIVE We sought to determine the tumor control rate and cranial nerve function outcomes in patients with vestibular schwannomas who were treated with proton beam stereotactic radiosurgery. METHODS Between November 1992 and August 2000, 88 patients with vestibular schwannomas were treated at the Harvard Cyclotron Laboratory with proton beam stereotactic radiosurgery in which two to four convergent fixed beams of 160-MeV protons were applied. The median transverse diameter was 16 mm (range, 2.5–35 mm), and the median tumor volume was 1.4 cm3 (range, 0.1–15.9 cm3). Surgical resection had been performed previously in 15 patients (17%). Facial nerve function (House-Brackmann Grade 1) and trigeminal nerve function were normal in 79 patients (89.8%). Eight patients (9%) had good or excellent hearing (Gardner-Robertson [GR] Grade 1), and 13 patients (15%) had serviceable hearing (GR Grade 2). A median dose of 12 cobalt Gray equivalents (range, 10–18 cobalt Gray equivalents) was prescribed to the 70 to 108% isodose lines (median, 70%). The median follow-up period was 38.7 months (range, 12–102.6 mo). RESULTS The actuarial 2- and 5-year tumor control rates were 95.3% (95% confidence interval [CI], 90.9–99.9%) and 93.6% (95% CI, 88.3–99.3%). Salvage radiosurgery was performed in one patient 32.5 months after treatment, and a craniotomy was required 19.1 months after treatment in another patient with hemorrhage in the vicinity of a stable tumor. Three patients (3.4%) underwent shunting for hydrocephalus, and a subsequent partial resection was performed in one of these patients. The actuarial 5-year cumulative radiological reduction rate was 94.7% (95% CI, 81.2–98.3%). Of the 21 patients (24%) with functional hearing (GR Grade 1 or 2), 7 (33.3%) retained serviceable hearing ability (GR Grade 2). Actuarial 5-year normal facial and trigeminal nerve function preservation rates were 91.1% (95% CI, 85–97.6%) and 89.4% (95% CI, 82–96.7%). Univariate analysis revealed that prescribed dose (P = 0.005), maximum dose (P = 0.006), and the inhomogeneity coefficient (P = 0.03) were associated with a significant risk of long-term facial neuropathy. No other cranial nerve deficits or cancer relapses were observed. CONCLUSION Proton beam stereotactic radiosurgery has been shown to be an effective means of tumor control. A high radiological response rate was observed. Excellent facial and trigeminal nerve function preservation rates were achieved. A reduced prescribed dose is associated with a significant decrease in facial neuropathy.

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Effectiveness and Toxicity of Fractionated Proton Beam Radiotherapy for Cranial Nerve Schwannoma Unsuitable for Stereotactic Radiosurgery

Frontiers in Oncology ◽

10.3389/fonc.2021.772831 ◽

2021 ◽

Vol 11 ◽

Author(s):

Tanja Eichkorn ◽

Sebastian Regnery ◽

Thomas Held ◽

Dorothea Kronsteiner ◽

Juliane Hörner-Rieber ◽

...

Keyword(s):

Stereotactic Radiosurgery ◽

Proton Beam ◽

Cranial Nerve ◽

Tumor Control ◽

Special Importance ◽

Nerve Function ◽

Proton Beam Radiotherapy ◽

Cranial Nerve Dysfunction ◽

Cranial Nerve Function

PurposeIn this benign tumor entity, preservation of cranial nerve function is of special importance. Due to its advantageous physical properties, proton beam radiotherapy (PRT) is a promising approach that spares healthy tissue. Could PRT go along with satisfactory preservation rates for cranial nerve function without compromising tumor control in patients with cranial nerve schwannoma unsuitable for stereotactic radiosurgery?MethodsWe analyzed 45 patients with cranial nerve schwannomas who underwent PRT between 2012 and 2020 at our institution. Response assessment was performed by MRI according to RECIST 1.1, and toxicity was graded following CTCAE 5.0.ResultsThe most common schwannoma origin was the vestibulocochlear nerve with 82.2%, followed by the trigeminal nerve with 8.9% and the glossopharyngeal nerve as well as the vagal nerve, both with each 4.4%. At radiotherapy start, 58% of cranial nerve schwannomas were progressive and 95.6% were symptomatic. Patients were treated with a median total dose of 54 Gy RBE in 1.8 Gy RBE per fraction. MRI during the median follow-up period of 42 months (IQR 26–61) revealed stable disease in 93.3% of the patients and partial regression in 6.7%. There was no case of progressive disease. New or worsening cranial nerve dysfunction was found in 20.0% of all patients, but always graded as CTCAE °I-II. In seven cases (16%), radiation-induced contrast enhancements (RICE) were detected after a median time of 14 months (range 2–26 months). RICE were asymptomatic (71%) or transient symptomatic (CTCAE °II; 29%). No CTCAE °III/IV toxicities were observed. Lesions regressed during the follow-up period in three of the seven cases, and no lesion progressed during the follow-up period.ConclusionThese data demonstrate excellent effectiveness with 100% local control in a median follow-up period of 3.6 years with a promising cranial nerve functional protection rate of 80%. RICE occurred in 16% of the patients after PRT and were not or only mildly symptomatic.

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184 Cranial Nerve Function Before and After Stereotactic Radiosurgery for Cavernous Sinus Meningiomas

Neurosurgery ◽

10.1227/01.neu.0000417774.86428.ea ◽

2012 ◽

Vol 71 (2) ◽

pp. E571-E572 ◽

Cited By ~ 2

Author(s):

Hideyuki Kano ◽

Kyung-Jae Park ◽

Aditya K. Iyer ◽

Ajay Niranjan ◽

John Flickinger ◽

...

Keyword(s):

Stereotactic Radiosurgery ◽

Cavernous Sinus ◽

Cranial Nerve ◽

Nerve Function ◽

Cranial Nerve Function ◽

Before And After

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Cranial Nerve Preservation and Outcomes after Stereotactic Radiosurgery for Jugular Foramen Schwannomas

Neurosurgery ◽

10.1227/01.neu.0000279726.90650.6d ◽

2007 ◽

Vol 61 (1) ◽

pp. 76-81 ◽

Cited By ~ 37

Author(s):

Juan J. Martin ◽

Douglas Kondziolka ◽

John C. Flickinger ◽

David Mathieu ◽

Ajay Niranjan ◽

...

Keyword(s):

Stereotactic Radiosurgery ◽

Cranial Nerve ◽

Gamma Knife Radiosurgery ◽

Jugular Foramen ◽

Tumor Control ◽

Lower Cranial Nerve ◽

Nerve Preservation ◽

Cranial Nerve Function ◽

Cranial Neuropathies ◽

Cranial Nerve Preservation

Abstract OBJECTIVE Jugular foramen region schwannomas are rare intracranial tumors that usually present with multiple lower cranial nerve deficits. For some patients, complete surgical resection is possible but may be associated with significant morbidity. Stereotactic radiosurgery is a minimally invasive alternative or adjunct to microsurgery for such tumors. We reviewed our clinical and imaging outcomes after patients underwent gamma knife radiosurgery for management of jugular foramen schwannomas. METHODS Thirty-four patients with 35 tumors (one patient had bilateral tumors) underwent radiosurgery between May 1990 and December 2005. Twenty-two patients had previous microsurgical resection and all patients experienced various cranial neuropathies. A median of six isocenters were used. Median marginal and maximum doses were 14 and 28 Gy, respectively. RESULTS None of the patients were lost to evaluation and the mean duration of follow-up was 83 months. Tumors regressed in 17 patients, remained stable in 16, and progressed in two. Five- and 10-year actuarial control rates were 97 and 94%, respectively. Preexisting cranial neuropathies improved in 20% and remained stable in 77% after radiosurgery. One patient worsened. The function of all previous intact nerves was preserved after radiosurgery. CONCLUSION Stereotactic radiosurgery proved to be a safe and effective management for newly diagnosed or residual jugular foramen schwannomas. Long-term tumor control rates and stability or improvement in cranial nerve function was confirmed.

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Does Prior Microsurgery Improve or Worsen the Outcomes of Stereotactic Radiosurgery for Cavernous Sinus Meningiomas?

Neurosurgery ◽

10.1227/01.neu.0000431471.64289.3d ◽

2013 ◽

Vol 73 (3) ◽

pp. 401-410 ◽

Cited By ~ 28

Author(s):

Hideyuki Kano ◽

Kyun-Jae Park ◽

Douglas Kondziolka ◽

Aditya Iyer ◽

Xiaomin Liu ◽

...

Keyword(s):

Stereotactic Radiosurgery ◽

Cavernous Sinus ◽

Cranial Nerve ◽

Progression Free Survival ◽

Tumor Control ◽

Improvement Rate ◽

Cranial Nerve Function ◽

Cranial Neuropathies ◽

Microsurgical Resection

Abstract BACKGROUND: Stereotactic radiosurgery (SRS) is an important option for patients with cavernous sinus meningiomas. OBJECTIVE: To evaluate cranial nerve outcomes in patients who underwent SRS for cavernous sinus meningiomas with or without prior microsurgery. METHODS: During a 23-year interval, 272 patients underwent Gamma Knife SRS for cavernous sinus meningiomas (70 men, 202 women; median age, 54 years). In this series, 99 patients underwent prior microsurgical resection. The median tumor volume was 7.9 cm3 and median marginal dose was 13 Gy. The median follow-up period was 62 months (range, 6-209 months). RESULTS: The progression-free survival after SRS was 96% at 3 years, 94% at 5 years, and 86% at 10 years. After SRS, 13 of 91 patients (14%) who underwent prior microsurgery had improvement of preexisting cranial nerve symptoms or signs. In comparison, 54 of 145 patients (37%) without prior microsurgery had improvement of preexisting cranial nerve symptoms or signs. The improvement rate of cranial nerve deficits after SRS in patients without prior microsurgery was 20% at 1 year, 34% at 2 years, 36% at 3 years, and 39% at 5 years. Patients who had not undergone prior microsurgery had significantly higher improvement rates of preexisting cranial nerve symptoms and signs (P = .001). After SRS, 29 patients (11%) developed new or worsened cranial nerve function. CONCLUSION: SRS provided long-term effective tumor control and a low risk of new cranial nerve deficits. Improvement in preexisting cranial neuropathies was detected in significantly more patients who had not undergone prior microsurgical procedures.

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RADT-16. HYPOFRACTIONATED RADIOTHERAPY AND STEREOTACTIC RADIOSURGERY FOR VESTIBULAR SCHWANNOMAS: A SYSTEMATIC REVIEW AND META-ANALYSIS

Neuro-Oncology ◽

10.1093/neuonc/noaa215.769 ◽

2020 ◽

Vol 22 (Supplement_2) ◽

pp. ii184-ii185

Author(s):

Umberto Tosi ◽

Sergio Guadix ◽

Anjile An ◽

Drew Wright ◽

Andrew Brandmaier ◽

...

Keyword(s):

Facial Nerve ◽

Stereotactic Radiosurgery ◽

Cranial Nerve ◽

Meta Analysis ◽

Post Treatment ◽

Vestibular Schwannomas ◽

Tumor Control ◽

Significant Heterogeneity ◽

Ovid Medline ◽

Cochrane Reviews

Abstract BACKGROUND Vestibular schwannomas (VS) are tumors of the cerebellopontine angle with significant morbidity, causing hearing loss, tinnitus, and trigeminal and facial nerve compromise. Surgical resection is complex and often results in comorbidities, with radiation therapy being used to achieve tumor control. Both single dose stereotactic radiosurgery (SRS) and, in recent years, hypofractionated stereotactic radiotherapy (hSRT), where a total 18-25 Gy dose is given in approximately 3-5 fractions, have been utilized. It remains unclear, however, how each of these approaches fares compared to the other. METHODS Ovid MEDLINE, EMBASE, CINAHL, and Cochrane Reviews were searched for studies either comparing hSRT with SRS or focusing on hSRT alone for the treatment of VS. Primary endpoints included tumor control, serviceable hearing, presence of tinnitus, and facial and trigeminal nerve symptoms. A random effects analysis was employed to compare pre- and post-treatment effects (hSRT alone) or SRS and hSRT outcomes (two-arm studies). RESULTS This analysis included 21 studies focusing on hSRT alone and 13 studies comparing SRS and hSRT. Significant heterogeneity was observed. Overall, when hSRT was analyzed alone, crude tumor control was achieved in 93% of 1571 patients at average follow-up of 49.9 months. There was no difference intra-group between pre- and post-treatment odds ratios (OR) of tinnitus, facial, or trigeminal impairment. However, serviceable hearing was diminished following hSRT (OR = 0.60, 95% CI: 0.44, 0.83, p = 0.002). Comparison with SRS showed no difference with respect to tumor control (p = 0.84), serviceable hearing (p = 0.65), trigeminal impairment (p = 0.96), or facial nerve impairment (p = 0.32). CONCLUSIONS hSRT achieved excellent tumor control and, with the exception of serviceable hearing, did not result in worse cranial nerve symptomatology. Analyzing two-arm studies showed that hSRT is a treatment modality comparable to SRS with respect to tumor control and cranial nerve comorbidities.

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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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Stereotactic radiosurgery for acoustic nerve tumors in patients with useful preoperative hearing: results at 2-year follow-up examination

Journal of Neurosurgery ◽

10.3171/jns.1994.80.6.1011 ◽

1994 ◽

Vol 80 (6) ◽

pp. 1011-1017 ◽

Cited By ~ 44

Author(s):

Olusola K. Ogunrinde ◽

L. Dade Lunsford ◽

John C. Flickinger ◽

Douglas Kondziolka

Keyword(s):

Stereotactic Radiosurgery ◽

Trigeminal Nerve ◽

Cranial Nerve ◽

Nerve Function ◽

Content Type ◽

Acoustic Neuromas ◽

Cranial Nerve Function ◽

Acoustic Nerve ◽

Radiation Beams ◽

Fine Print

✓ Twenty patients with acoustic nerve tumors (mean diameter ≤ 30 mm) and useful preoperative hearing were examined 2 years after stereotactic radiosurgery to determine the effectiveness of the surgery in the control of tumor growth and the preservation of cranial nerve function. Results showed tumor volume stabilization (12 cases) or reduction (seven cases) was achieved in a total of 19 patients (95%). Useful hearing (defined as Gardner and Robertson Class I or II) preservation was obtained in 100% of cases immediately postoperatively, 50% at 6 months, and 45% at both 1 and 2 years. Two years after stereotactic radiosurgery, facial nerve function was preserved in 90% of patients and 75% continued to have normal trigeminal nerve function. All patients returned to and maintained their preoperative functional status within 3 to 5 days after radiosurgery. These findings indicate that stereotactic radiosurgery with multiple isocenters and narrow radiation beams is a safe and effective management strategy for progressive acoustic nerve tumors. Auditory, facial, and trigeminal nerve function can be preserved in most patients. Prevention of further growth and preservation of cranial nerve function appear to be satisfactory goals in the current management of patients with acoustic neuromas.

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Outcomes of Stereotactic Radiosurgery for Large Vestibular Schwannomas: a Systematic Review and Meta-Analysis

Neuro-Oncology Practice ◽

10.1093/nop/npab011 ◽

2021 ◽

Author(s):

Umberto Tosi ◽

Miguel E Tusa Lavieri ◽

Anjile An ◽

Omri Maayan ◽

Sergio W Guadix ◽

...

Keyword(s):

Facial Nerve ◽

Stereotactic Radiosurgery ◽

Cranial Nerve ◽

Meta Analysis ◽

Management Strategies ◽

Treatment Protocol ◽

Vestibular Schwannomas ◽

Treatment Modalities ◽

Tumor Control ◽

Pre Treatment

Abstract Background Large vestibular schwannomas (VS) pose a treatment challenge for both microsurgery (MS) and stereotactic radiosurgery (SRS). Technical developments have allowed for safer irradiation of large tumors. It remains unclear if SRS can achieve appropriate tumor control and acceptable cranial nerve toxicities. In this study, we assess outcomes of irradiation for large VS. Methods PubMed MEDLINE, EMBASE, Web of Science, and Cochrane were searched for all the studies assessing SRS outcome in large VS. Primary endpoints included clinical and radiographic tumor control, need for salvage surgery, serviceable hearing, cranial nerve V and VII impairment, presence of hydrocephalus requiring shunting, and presence of vertigo / dizziness. Results 22 studies were identified that met selection criteria for analysis from an initial pool of 1272 reports. They were evaluated according to treatment protocol: (i) single dose SRS (13 studies, 483 patients), (ii) combination of MS and SRS (7 studies, 182 patients), and (iii) fractionated SRS (3 studies, 82 patients). Tumor control was achieved in 89%, 94%, and 91% of patients, respectively. Odds ratio of post- over pre-treatment serviceable hearing were 0.42 (p < 0.01), 0.47 (p = 0.05), and 0.60 (p = 0.22); for facial nerve impairment, these OR were 1.08 (p = 0.69), 3.45 (p = 0.28), and 0.87 (p = 0.71) respectively. Conclusions The management of large VS remains challenging. All treatment modalities resulted in high tumor control rates and worsening of pre-treatment hearing. None, however, caused significant facial nerve impairment, suggesting that management strategies incorporating focal irradiation can be successful.

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