[Radiosurgical irradiation of patients with cerebral AVM on the Gamma knife].

UNLABELLED: Arterio-venous malformation (AVM) of the brain are congenital malformations of cerebral vessels in the embryonic period. Standards in AVM treatment is currently applying the endovascular technique, microneurosurgical removal and stereotactic radiation. MATERIALS AND METHODS: In the period from 2005 to 2011, in 139 patients with arteriovenous malformations of the brain were treated using "Gamma Knife". 89 (64%) of 139 patients suffered bleeding in anamnesis. Paroxysmal symptoms of varying severity dominated in the clinical picture of 35 (27%) patients. Previous microsurgical resection was performed in 10 patients. 28 patients experienced a partial embolization of vascular malformations before radiosurgery. A boundary value radiation dose ranged from 18 to 28 Gy (mean dose 20 Gy), day dose was in the range of 40-80% (average 50% isodose). Maximum dose ranged between 18-60 Gy (mean dose of 38 Gy.). RESULTS: Control angiography or spiral CT screening angiography was performed in all 85 patients who were treated with follow-up data for more than two years, showed that total obliteration occurred in 75% of cases. Frequency of symptomatic radiation reactions was less than 5%. After two years or more after treatment, complete obliteration was observed in 74% of patients. CONCLUSIONS: Higher frequency of AVM obliteration was seen with up to 2 cc. and the irradiation dose of at least 24 Gy.

[Stereotactic radiotherapy and radiosurgery in treatment of patients with deep-seated pilocytic astrocytomas].

Pilocytic astrocytoma (PA) is a low-grade glial tumor (WHO grade I) with predominant occurrence in pediatric patients. According to many authors, stereotactic radiosurgery (SRS) and radiotherapy (SRT) promote long-term remission or retardation of tumor progression in patients with in inoperable lesions after incomplete resection or recurrence. Therefore it is essential to determine the role of SRS and SRT in complex management of patients with deep-seated PA. Since April 2005 till May 2010 101 patient with intracranial PA was treated in department for radiation therapy of Burdenko Neurosurgical Institute. The series consisted of 70 pediatric patients (below 17 years inclusively) and 31 adults, of them--51 male and 50 female patients. Mean age was 15.1 years (9.8 years in children and 28.7 in adults). In 90 patients (89.2%) tumors were previously histologically verified (tumor resection in 83 cases and biopsy in 7). In 11 (10.8%) patients diagnosis of PA was based on clinical and neurovisualization data. In most cases SRT (66 (66.3%) patients) was preformed, the rest 35 (34.7%) patients were treated by SRS. Median follow-up from the onset of disease reached 52 months (2-228 months). Catamnestic data were available in 88 (87%) patients. By the end of catamnestic follow-up (December 2010) 87 (98.8%) patients treated by SRS and SRT were alive. Median follow-up from the start of radiation treatment was 22.7 months (6-60 months). Progression of tumor was observed in 20 patients (22.7%), in 18 of them due to cyst growth. 18 patients were reoperated. In 12 operated patients histological examination and its comparative analysis were performed. We found that alterations in the tumor tissue, accompanied by regression of solid component and progression of cystic portion, represent reactive-degenerative changes in the tumor as a consequence of radiation-induced pathomorphism. SRS and STR are effective techniques for treatment of patients with primary and recurrent PA despite regardless of localization of the tumor. There procedures should be performed shortly after non-radical resection. Control of tumor growth by the present time (median follow-up is 22.7 months) reaches 98%. "Progression" of the tumor due to enlargement of cystic portion shortly after SRT and SRS represents reactive-degenerative alterations in the tumor tissue and should not be evaluated as true recurrence; without neurological deterioration these cases do not require special treatment.

[Application of "Gamma-knife" radiosurgery in treatment of intracranial metastases of extracranial malignant tumors].

Treatment of intracerebral metastases is one of the key problems in neurooncology. Modern methods of combined treatment do not significantly affect terms of survival. Quality of life during the whole period of treatment depends on selected tactics. We summarized our experience of treatment of 119 patients with cerebral metastases of extracranial tumors with "Gamma-knife" stereotactic radiosurgery (GKSRS) during 2005 and 2006 years. "Leksell Gamma-knife C" was used for treatment procedures. Primary tumor was located in lung in 35 cases, in breast in 32 cases. Renal cancer metastases were less common (15 cases) as well as skin melanoma (14), colon cancer (8) and other localizations (6 cases). Total amount of treated metastases was 628. Marginal doses ranged between 15 and 24 Gy. During followup 77 patients were examined 153 times by contrast-enhanced MRI every 3 months. Mean follow-up period was 194.6 days (6.5 months). In 68 cases (88.3%) GKSRS provided total tumor control of 446 irradiated lesions (92%). Median survival after GKSRS was 8.2 months. All patients were assessed using RPA prognostic criteria. The best prognosis for life ( > 1 year) was observed in RPA I class patients. Median survival in patients with initial Karnofsky performance level < 70% (RPA III class) did not exceed 3.5 months. Presence of circumscribed brain involvement (less than 10 foci) is associated with more favorable prognosis (median survival is increased to 9.4 months). In patients with disseminated brain involvement (more that 10 metastases) survival median was 3.8 months (p < 0.05). GKSRS is minimally invasive, safe and effective method for treatment of intracerebral metastases of all main histological types of extracranial tumors. Local tumor control is observed in 88% of patients. Life expectancy prognosis depends on activity of extracranial process, initial condition of patient by the moment of treatment and initial spread of metastatic brain involvement.

[Radiation necrosis after stereotactic radiosurgery for benign glioma].

Stereotactic radiosurgery (SRS) becomes more widely used in treatment of patients with intracranial tumors. In spite of low invasiveness this method produces risk of development of radiation-induced complications including symptomatic focal necrosis. Authors report a case of radiation-induced necrosis occurred in a patient treated for benign glioma using Leksell Gamma-Knife. Morphological features, risk factors, incidence, differential diagnosis and treatment of cerebral radiation-induced necroses are briefly discussed in this article.

[First experience with a Gamma-knife unit used for radiosurgical treatment for intracranial space-occupying lesions].

A Gamma-Knife unit that is currently the gold standard in radiosurgery was first used in clinical practice in 1968. The essence of the radiosurgical treatment is to apply the stereotactic technique to high-precision irradiation of small intracranial targets by narrow beams of ionizing radiation from external sources. Three hundred and six patients with various intracranial diseases (137 with malignant tumors, 136 with benign tumors, and 33 patients with vascular diseases) underwent radiosurgery on a Gamma-Knife unit for over 1.5 years, from May 2005 to October 2006. A total of 329 irradiation sessions were performed. By summing up the first results, it can be noted that stereotactic radiosurgery using a Gamma-Knife unit is an effective and rather safe technique in the treatment of patients with various types of intracranial pathology, which maintains the high quality of life, reduces the likelihood of development of different neurological disorders after treatment and avoids the risk of operative complications. The possibility of performing outpatient treatment for a diversity of diseases without mandatory anesthesiological, ICU, and rehabilitative maintenance, determines the potential economic efficiency of this treatment.