[Features of course of pain syndrome in patients with schwannomatosis]. / Osobennosti techeniya bolevogo sindroma u patsientov s shvannomatozami.

OBJECTIVE: To identify the characteristics of pain syndrome in patients with schwannomas depending on genetic predisposition. MATERIAL AND METHODS: The study included 46 patients with peripheral, spinal and intracranial schwannomas, corresponding to the schwannomatosis phenotype according to the 2022 clinical criteria. All patients underwent sequencing of the LZRT1, Nf2 and SMARCB1 and a copy number study in the NF2. RESULTS: The most severe widespread pain was observed in patients with pathogenic LZRT1 variants, while patients with mosaic variants may not even have local tumor-related pain. Patients with SMARCB1variants may have no pain or have localized pain that responds well to surgical treatment. CONCLUSION: Further studies of the molecular features of schwannomatosis and driver mutations in the pathogenesis of pain are necessary to improve the effectiveness of pain therapy in this group of patients. Schwannomatosis is a disease from the group of neurofibromatosis, manifested by the development of multiple schwannomas. Neuropathic pain is one of the main symptoms characteristic of peripheral schwannomas, however, the severity and prevalence of the pain syndrome does not always correlate with the location of the tumors. According to modern concepts, the key factors influencing the characteristics of the pain syndrome are the target gene and the type of pathogenic variant. The most severe widespread pain is observed in patients with pathogenic variants in the LZRT1 gene, while patients with mosaic variants may not even have local pain associated with tumors. Patients with variants in SMARCB1 may have no pain or localized pain that responds well to surgical treatment.

[Stereotactic irradiation for optic nerve hemangioblastoma associated with Von Hippel-Lindau disease: a case report and literature review]. / Stereotaksicheskoe obluchenie gemangioblastomy zritel'nogo nerva, assotsiirovannogo s bolezn'yu fon Gippelya­Lindau: klinicheskii sluchai i obzor literatury.

Hemangioblastoma is a benign tumor of the central nervous system arising sporadically or as a component of Von Hippel-Lindau disease. Von Hippel-Lindau disease is a rare autosomal dominant hereditary syndrome with various phenotypes caused by VHL gene variants. To date, only about 40 cases of optic nerve hemangioblastoma have been described in the literature. Stereotactic irradiation may be effective for supratentorial hemangioblastomas including lesions of optic nerves. The authors describe a rare case of stereotactic irradiation of intraorbital hemangioblastoma of the optic nerve in a patient with Von Hippel-Lindau disease.

[New classification and approaches to the treatment of schwannomatosis]. / Novaya klassifikatsiya i podkhody k terapii shvannomatozov.

Schwannomatoses is a new classification unit for all the hereditary diseases caused by chromosome 22 damage followed by multiple benign neoplasms of the peripheral and central nervous system. Schwannomatosis occurs as a result of damage to different genes: NF2, SMARCB1, LZRT1, loss of heterozygosity of the long arm of chromosome 22. Nevertheless, clinical manifestations are similar. Molecular diagnostics not only confirms the diagnosis, but also predicts the course of disease. Thus, the most severe clinical manifestations are observed in patients with violation of semantic sequences and reading frame shift in exons 2-13 of the NF2 gene. A more favorable course with less number of tumors is observed in patients with somatic mosaicism. Stereotactic irradiation and surgery are the main treatment options for schwannomatosis. However, there is evidence of effective targeted therapy with bevacizumab (inhibitor of vascular endothelial growth factor). Bevacizumab is used in patients with bilateral vestibular schwannomas and high risk of hearing loss, as well as for intramedullary tumor growth control.

[Molecular genetic features of meningiomas]. / Molekulyarno-geneticheskie osobennosti meningiom.

Meningioma is the most common primary tumor of the central nervous system. Traditional classification is based on histological properties of tumors and distinguishes different grades of meningioma malignancy. However, knowledge about different molecular mechanisms of tumor provided new data on genetic features of meningiomas. The authors analyze current available data on the main driver mutations, new classifications based on molecular genetic characteristics and potential targets for therapy.

[Trigeminal neuromas: modern diagnosis and treatment]. / Trigeminal'nye nevrinomy: sovremennaya diagnostika i lechenie.

Trigeminal neuroma (TN) is a benign neoplasm arising from trigeminal nerve sheath. The tumor can grow from any part of the nerve from the root in posterior cranial fossa to peripheral extracranial branches. Symptoms of trigeminal neuroma are variable and usually depend on location and dimensions of tumor. We present a review devoted to the problem of TN. Surgery was the only possible option in patients with TN for a long time. However, radiotherapy became one of the options and sometimes alternative to surgical treatment since the late 1980s. Besides active management of patients with TN, follow-up with regular radiographic control of small asymptomatic tumors also seems to be reasonable. When evaluating treatment outcomes, physicians consider quality of life and return to previous work and activity in addition to resection quality, neurological impairment, relapse-free period and tumor growth control. However, assessment of these indicators after certain treatment is rare. Thus, it is difficult to determine treatment strategy with maximum ratio of effectiveness and quality of life. Therefore, optimization of TN treatment is currently an urgent problem that requires further study.

[Prognostic value of TERT mutation in adults with primary glioblastomas. Preliminary results]. / Prognosticheskoe znachenie mutatsii gena TERT u vzroslykh patsientov s pervichnymi glioblastomami. Predvaritel'nye rezul'taty.

Glioblastoma (GB) is one of the most aggressive primary brain tumors. Analysis of molecular genetic factors affecting prognosis in patients with GB is an important direction of fundamental and clinical researches. There are literature data on the effect of TERT gene mutations, MGMT methylation and IDH1/2 status on overall survival in patients with GB. OBJECTIVE: To evaluate the incidence of TERT gene promoter mutations in adults with primary GB and to analyze the effect of TERT mutations on relapse-free and overall survival, as well as interaction of these mutations with MGMT gene methylation and IDH1/2 mutations. MATERIAL AND METHODS: The study included 56 patients (26 women and 30 men) with histologically verified GB in which genetic and molecular investigations were performed. There were patients with life duration >3 years (n=15) and people with an extremely unfavorable course of disease (14 ones with primary multiple GB, 8 patients with GB metastases including extraaxial and 8 patients with life duration <8 months). TERT gene sequencingwas performed in all the cases, IDH1/2 status was known for 41 patients, MGMT status - for 23 patients. RESULTS: Overall survival significantly differed between patients with and without TERT mutation (56 vs 17 months, p>0.05). TERT gene promoter mutation increased the effect of IDH1/2 mutations on overall and relapse-free survival (p=0.011). No TERT and IDH1/2 gene mutations worsened prognosis. There were no significant differences between TERT status and development of primary multiple GBs, as well as extra- and intracranial metastases. CONCLUSION: Thus, the combined status of IDH1/2 and TERT mutations was a factor of better prognosis and can be proposed in clinical practice.

[Rosai-Dorfman intracranial histiocytosis: case report and literature review]. / Intrakranial'nyi gistiotsitoz Rozai­Dorfmana: sluchai iz praktiki i obzor literatury.

Histiocytosis is a group of idiopathic diseases accompanied by metabolic disorders and accumulation of metabolic products in histiocytes. Isolated Rosai-Dorfman histiocytosis of central nervous system is observed in less than 5% of cases. The authors report treatment and follow-up of a patient with intracranial Rosai-Dorfman disease. There were symptoms of lesion of the left cerebellopontine angle and epileptic seizures. Preoperative MRI identified two tumors (posterior cranial fossa on the left and right-sided parasagittal neoplasm). The authors carried out total resection of supratentorial tumor, after 3 weeks - subtotal resection of tumor in posterior cranial fossa. No recurrence after total resection was observed. Irradiation of infratentorial tumor with a total focal dose of 50 Gy after 6 months resulted tumor shrinkage throughout 12 months. Radiotherapy with the same dose was repeated throughout subsequent 12-month follow-up period due to progression of this focus. This treatment had a positive effect, but new skull base foci occurred. The authors emphasize the effectiveness of total resection and lower efficiency of subtotal excision combined with radiotherapy.

[Investigation of the metabolic features of primary glioblastomas by Tc-MIBI SPECT/CT and evaluation of their effect on disease prognosis]. / Issledovanie metabolicheskikh osobennostei pervichnykh glioblastom metodom OFÉKT-KT s Tc-MIBI s otsenkoi ikh vliianiia na prognoz zabolevaniia.

OBJECTIVE: To study the effect of metabolic characteristics of the tumor determined by 99mTc-MIBI single-photon emission computed tomography (SPECT) and various molecular genetic features on the outcomes of combination treatment of hemispheric glioblastomas. MATERIAL AND METHODS: This single-center prospective cohort study involved 68 patients aged 25-78 years (38 males and 30 females) with primary glioblastomas. Hypermetylation of the promotor region of the MGMT gene was observed in 24 (42%) out of 57 patients. The IDH1 mutation was revealed in two (3.5%) patients. The catamnestic data were available for 66 out of 68 patients. The first SPECT/CT study was carried out before chemoradiation therapy; the second SPECT/CT study was performed after the chemoradiation therapy. In each study, quantitative measures were calculated for the early (15-30 min after the patient had received a radiopharmaceutical) and late (after 45-60 min) phases. RESULTS: The actuarial survival rates after 12 and 24 months were 69.6 and 29.1%, respectively. The median overall survival rate was 17.5 months (95% CI 12.9-20.3). Favorable prognostic factors for overall survival included the higher uptake index (UI) in the late phase compared to UI in the early phase of the first SPECT/CT study (p=0.0444), dynamics of changes in UI during the second SPECT/CT compared to baseline over 10% (p=0.0436), MGMT hypermethylation (p=0.0003), and duration of the period between surgery and initiation of chemoradiotherapy being <1 month (p=0.0008). No statistically significant correlations were revealed between the absolute UI values in the tumor and its molecular genetic features. CONCLUSION: The 99mTc-MIBI SPECT/CT can be used to predict overall survival and to plan radiation therapy of glioblastoma as it is more readily available at primary healthcare facilities than amino acid PET.

[The phenomenon of long-term survival in glioblastoma patients. Part I: the role of clinical and demographic factors and an IDH1 mutation (R 132 H)]. / Fenomen dlitel'noi vyzhivaemosti patsientov s glioblastomami. Chast' I: rol' kliniko-demograficheskikh faktorov i mutatsii IDH1 (R 132 H).

The median overall survival of glioblastoma patients is about 15 months. Only a small number of patients survive 3 years. The factors of a favorable prognosis for the 'longevity phenomenon' in glioblastoma patients are not fully understood. OBJECTIVE: to determine the occurrence rate of long-living patients with glioblastomas, identify clinical predictors of a favorable prognosis, and identify the presence and prognostic significance of an IDH1 mutation. MATERIAL AND METHODS: Among 1494 patients operated on for glioblastoma at the Burdenko Neurosurgical Institute from 2007 to 2012, there were 84 (5.6%) patients who lived more than 3 years after primary surgery. In all the cases, histological specimens were reviewed, and immunohistochemical detection of a mutant IDH1 protein was performed. Overall survival was calculated from the time of first surgery to the date of the last consultation or death, and the recurrence-free period was calculated from the time of first surgery to MRI-verified tumor progression. RESULTS: The median age of long-living patients with glioblastoma was 45 years (19-65 years). All tumors were located supratentorially. The median Karnofsky performance status score at the time of surgery was 80 (range, 70-100). All patients underwent microsurgical resection of the tumor, followed by chemoradiotherapy. The median recurrence-free period was 36 months (5-98 months). Overall survival of 48, 60, and 84 months was achieved in 23, 15 and 6% of patients, respectively. Among 49 specimens available for the IDH1 analysis, 14 (28.6%) specimens had a mutant protein. There was no significant difference in survival rates in patients with positive and negative results for IDH1 (44.1 vs. 40.8 months; p>0.05). CONCLUSION: The significance of various factors that may be predictors of a favorable course of the disease is discussed in the literature. This work is the first part of analysis of prognostically significant factors positively affecting overall survival of glioblastoma patients. In our series, the predictors of a favorable prognosis for long-living patients with the verified diagnosis of glioblastoma were as follows: young age, the supratentorial location of the tumor, a high Karnofsky score before surgery, and tumor resection. In our series, we used immunohistochemical tests and found no prognostic significance of the IDH1 gene mutation; further analysis will require application of direct sequencing. We plan to study other morphological and molecular genetic features of tumors, which explain prolonged survival of glioblastoma patients, as well as the role of various types of combined chemoradiation treatment.

[SCT perfusion in the diagnosis of sellar and parasellar tumors].

UNLABELLED: The study is devoted to the use of a minimally invasive method of SCT perfusion for the differential diagnosis of sellar and pаrаsellar tumors. Given a wide differential diagnostic range of tumors occurring in this area, the tumor perfusion indicators were used as an auxiliary diagnostic criterion. MATERIAL AND METHODS: The study analyzed outcomes in 115 patients with various tumors of the sellar area who underwent surgery or biopsy for histological verification of the diagnosis. RESULTS: The statistically significant differences were obtained for certain groups of tumors based on the values of hemodynamic parameters (p<0.05) that enable, with a high confidence, making a conclusion on the histologic type of most tumors. CONCLUSION: These findings demonstrated that SCT perfusion is a highly informative method of the preoperative differential diagnosis of these tumors. The sensitivity and specificity of SCT perfusion in the study were 100% and 81.2%, respectively.

[Stereotactic radiotherapy for spinal meningiomas and neurinomas].

INTRODUCTION: Over the past decades, stereotactic conformal radiotherapy of intracranial meningiomas and schwannomas has been recognized as an effective and safe procedure. Due to the wide use of the CyberKnife system and the procedure of extracranial stereotactic radiotherapy and radiosurgery, the positive experience can be used to treat spinal tumors. This study assessed the effectiveness of stereotactic radiaotherapy of spinal meningiomas and neurinomas using the CyberKnife system. MATERIAL AND METHODS: 46 patients (34 females and 12 males) received treatment between November 2009 and December 2013 (65 tumor nodules). The median age of patients receiving radiotherapy was 49 years (range: 20 to 82 years). Twenty neoplasms were subjected to surgical treatment. In 11 patients, formation of the recurrent tumor foci following treatment was observed along with the systemic disease, neurofibromatosis. Six patients had multiple meningiomas. The median total dose of radiation therapy of neurinomas was 13.6 Gy (12.1-14.1 Gy) per fraction; up to 18.2 Gy (16.0-21.1 Gy) per three fractions; and up to 25.6 Gy (24.8-27.6 Gy) per five fractions. Higher doses were used for meningiomas: 15.9 Gy (14.1-16.2 Gy) per fraction; 20.9 Gy (19.5-21.1 Gy) per three fractions; and 27.5 Gy (25.0-29.9 Gy) per five fractions. The load to 0.15 cm3 of the spinal cord was no higher than the maximum permissible load of 12 Gy per fraction. The mean catamnestic follow-up was 18.1 (4-52) months: 21,1 (4-52) months for neurinomas and 18 (4-31) months for meningiomas. We have not observed complete tumor elimination (i.e., complete response to radiation therapy) in our series. Partial response was observed in 9 (13.8%) cases; stabilization was achieved in 54 (83.1%) cases; and tumor continued to grow in 2 (3.1%) cases. The patients' status was evaluated using the Frankel, the Karnofsky, and the VAS scales. CONCLUSIONS: Our findings clearly demonstrate the short-term benefits of using CyberKnife radiotherapy for benign spinal cord tumors. The catamnestic follow-up needs to be extended to elaborate recommendations for radiation. The progress in this therapy type will considerably improve the quality of medical care provided to this cohort of patients.

[Malignant B-сell lymphoma of the anterior visual pathway].

This work was aimed at studying the optimal diagnosis methods and features of clinical signs of malignant B-cell lymphoma of the anterior visual pathways and choosing the most reasonable treatment method. Six immunocompetent patients with lymphomas in the chiasm-sellar region were examined. The outcomes of high-dose methothrexate chemotherapy and radiotherapy in these patients are analyzed.

[Application of robotized radiosurgical system CyberKnife for the treatment of neurosurgical patients].

Robotized system for radiosurgery CyberKnife (Accuray Inc., USA) is the first device dedicated and optimized for advanced irradiation during 1-7 fractions (i.e. radiosurgery and hypofractionation). CyberKnife is characterized by elaborate guidance system, high precision of dose delivery, possibility of conformal dose distributions with high gradient of target borderline dose which is most important in proximity of critical structures. The first CyberKnife system in Russia was installed in Burdenko Neurosurgery Institute. The paper presents 2-year experience of treating patients using CyberKnife. From April 2009 till October 2011 896 patients were treated using CyberKnife. Mean age was 48 years. Overall number of sessions was 2626. Radiosurgical procedures were performed in 21.8% of patients. 91% of cases were treated for intracranial lesions. Limited follow-up period in all kinds of pathology demonstrated results consistent with standard fractionation or radiosurgery. The rates of observed complications were also comparable with accepted techniques. CyberKnife system plays significant role in everyday activity of department of radiation therapy. In careful and thorough selection of patients it allows efficient and high-quality treatment of patients with neurosurgical diseases.

[First experience of stereotactic radiation therapy for vestibular schwannoma using CyberKnife].

Currently stereotactic radiosurgery has become the treatment of choice in small vestibular schwannomas. This paper discusses our first experience of application of CyberKnife system for stereotactic irradiation of these tumors. From April 2009 till June 2011 we treated 62 patients (35 female and 27 male) with vestibular schwannomas. Stereotactic radiosurgery using CyberKnife system was performed in 33 patients. Mean tumor volume was 2 +/- 1.4 cm3. Hypofractionated treatment was used in 30 cases (31 tumor). Mean tumor volume reached was 7 +/- 6.2 cm3 (range - 0.5-31.3 cm3). In a case of a patient with NF2 simultaneous irradiation of bilateral tumors was performed. Most frequently we applied 3 fractions 6 Gy each (17 observations of 31, or 55%) and 5 fractions with mean dose 5 Cy (10 cases, or 32%). Follow-up period varied from 1 to 26 months (mean 9 +/- 4.5 months). By the end of this study (June 30, 2011) surgical resection was required in the only case of 47-years old male patient with cystic schwannoma of left vestibular nerve 5 months after radiation treatment, due to progressive growth of the cyst and increased brainstem compression. Tumor growth control was established in 97.5% of cases. Stabilization of auditory function was achieved in 77.5% of series. Effective hearing was preserved in 75% of patients. Facial nerve palsy after stereotactic radiation treatment was observed in 2 cases (3%). Incidence of trigeminal nerve dysfunction was significantly higher: sensation disturbances occurred in 6 (10%) patients: 3% after radiosurgery and 16.7% after hypofractionation. We did not obtain significant correlations between risk of cranial nerve complications and dosimetric or demographic factors. However we observed stable tendency: larger initial volume of the tumor and presence of trigeminal nerve dysfunction before treatment were poor prognostic factors for trigeminal neuropathy. Stereotactic irradiation using CyberKnife system is effective and sufficiently safe technique for management of vestibular schwannoma. The paper demonstrates high rates of tumor stabilization, hearing preservation and minimal incidence of complications associated with trigeminal or facial nerve.

[Early results of irradiation of intracranial meningiomas using CyberKnife].

Meningiomas are frequently diagnosed intracranial lesions which cannot be resected radically in the majority of cases. Traditional radiotherapeutical techniques allow control of tumor growth in such situations. CyberKnife system may be used for radiosurgery and in sight hypofractionation. During 27 months 231 patient with intracranial meningiomas of different localization was treated in department for radiation therapy of Burdenko Neurosurgical Institute using CyberKnife system (Accuray Inc., USA). Mean age was 53 years. 55% of patients underwent previous surgical treatment, and diagnosis of meningioma was histologically verified. In 231 patient 374 targets were irradiated. Mean volume of irradiation reached 15.8 cm3 (range - 0.73-108.5 cm3). In 89% of cases hypofractionated therapy was used, in 10.1% we performed radiosurgery. Catamnestic data were available in 80 patients. Mean follow-up period was 11.6 months (6-27 months). Control of tumor growth was established in 100% of cases with WHO grade I tumors, in 66.7% of WHO grade II tumors and 60% in WHO grade III tumors. Deterioration after radiation treatment was observed in 16% of cases of 75 with control of tumor growth. In 8 cases worsening was due to radiation-induced reactions verified by MRI studies. Radiosurgical and hypofractionated treatment of meningiomas using CyberKnife is actual and highly-effective technique. Further investigations are needed to determine optimal standards of hypofractionated radiotherapy of meningiomas.

[First experience of CyberKnife stereotactic radiotherapy for glomus jugulare tumors].

Glomus jugulare tumors (GJT) (AKA paraganglioma or chemodecroma) make 0.6% of head and neck tumors and 80% of jugular foramen lesions. Recently different types of stereotactic radiotherapy are actively used in their treatment. The given paper summarizes our first experience of using CyberKnife system in management of patients with paragangliomas. Since April 2009 till September 2011 34 patients with GJT were treated in department for radiation therapy of Burdenko Neurosurgical Institute using CyberKnife system. Mean age was 50.5 years (range 26-75 years). Mean volume of treated lesions was 14.6 +/- 10.96 cm3 (range--1.04-37.4 cm3). Stereotactic radiosurgery was performed in 4 patients. Mean prescribed dose was 17 +/- 3.1 Gy (13.7-22 Gy). 30 patients received hypofractionation treatment (3-7 fractions with total dose 18-35 Gy). Mean follow-up period in our series was 8 months (1-20 months). Control of tumor growth reached 100% because none of the patients needed any additional therapy (microsurgical resection or repeated radiotherapy). Persistent trigeminal neuropathy was observed in 1 case (5%). There were no constant impairment of VII, IX, X, XII and XIII cranial nerves in the series. Stabilization of auditory function was present in 9 (82%) of 11 patients with initially preserved hearing. Preservation of effective hearing was observed in 75% of patients. Stereotactic radiosurgery and hypofractionation using CyberKnife system are effective modalities in management of such complex neurosurgical disease as GJT. Neurological deterioration after radiation treatment is extremely rare and in most cases is transient.

[CyberKnife stereotactic radiotherapy for mass lesions of the spinal cord and spine].

Introduction of a novel technology of stereotactic radiation treatment using linear accelerators, refining of systems for visualization and guidance provided rapid development of extracranial radiosurgery. Nowadays there is a possibility of precise stereotactic irradiation of lesions with different size and localization. One of the most actual and promising indications for radiosurgery are different primary and metastatic lesions and arteriovenous malformations of spinal cord and spine. Radiosurgery and hypofractionated radiotherapy with precise dose delivery during one or several sessions allow effective and safe treatment of neoplasms with any degree of radioresistance. This paper contains analysis of the first Russian experience of stereotactic radiation treatment of lesions of spinal cord and spine using robotized system CyberKnife (Accuray Inc., USA).

[Linear accelerator-based stereotactic radiotherapy and radiosurgery in treatment of neurosurgical patients].

Radiation methods are essential in management of certain types of neurooncological, neurovascular and functional brain pathology. Application of stereotactic technique of irradiation allows sufficient damaging impact on target (tumor, AVM, functional structures) and maximal protection of surrounding brain tissues. Indications to radiation treatment of intracranial lesions are expanding with evolution of stereotactic methods. The paper deals with the first experience of linear accelerator-based treatment of patients with intracranial neurosurgical pathology in this country. Techniques of stereotactic radiotherapy (SRT) and radiosurgery (SRS), indications to SRS and SRT in different modes of fractioning are described in details. Additionally specific complications, radiation reactions and feasibility of neurovisualization in diagnosis of radiation-induced brain damage are discussed.

[Stereotactic radiotherapy and radiosurgery in treatment of patients with intracranial schwannomas].

Aim of this study is to assess the role of stereotactic radiosurgery (SRS) and radiotherapy (SRT) in management of cranial nerves schwannomas by analysis of tumor control, clinical response and variables affecting treatment outcomes. Between April 2005 and January 2009 patients with schwannomas of VIII (63), V (14) and caudal nerves (2) were treated in Burdenko Moscow Neurosurgical Institute using linear accelerator. Mean age was 49 years (13-82). In 42 cases radiation treatment was preceded by surgical resection. 13 patients had type I or II neurofibromatosis. Mean volume of the tumor was 3.9 cm3 (0.5-14.4 cm3) and 13.4 cm3 (2.8-41.3 cm3) for SRS and SRT, respectively. Mean SRS dose was 12 Gy (10.8-14.4 Gy) for vestibular schwannomas and 15 Gy (13.2-18 Gy) for schwannomas of other nerves. In hypofractionated SRT the dose of 35 Gy was delivered in 7 fractions or 30 Gy in 6 fractions. In cases of classical fractioning total dose of 50-60 Gy was divided into daily fractions of 1.8-2.0 Gy. Radiographic tumor control rate reached 97.5% at the last follow-up. 5 patients experienced trigeminal dysfunction, it was transient in 3 cases and persistent in 2. Permanent decline in House-Brackmann facial nerve scale developed in 2 of 79 patients. After treatment effective hearing (class I-II) was preserved in 7 of 9 patients (67%) who had same level of hearing before SRS. Linear accelerator-based stereotactic radiation treatment provides long-term tumor control associated with high rates of preservation of neurological functions. No further tumor surgery was necessary in 100% of cases with solitary tumors with a minimal follow-up of 5 years.

[Linear accelerator-based stereotactic radiotherapy in combined treatment of skull base chordomas].

Short-term results of postoperative stereotactic linear accelerator-based radiation treatment of 18 patients with cranial base chordomas are analyzed. Total dose was 70 Gy or more. Control of tumor growth confirmed by CT and/or MRI was achieved in 15 cases (83%). Only 1 patient had complication--visual deficit which resolved after 3 months. Control group consisted of 73 patients treated only surgically. 38% of cases in this group were recurrence-free. The study has demonstrated effectiveness of radiotherapy of skull base chordomas.