チエルノフ　ミハイル    Department   School of Medicine(Tokyo Women's Medical University Adachi Medical Center), School of Medicine    Position   Assistant Professor
Language	English
Title	Current status of ocular gamma knife surgery in Europe.
Conference	ISRS2017 Congress
Conference Type	International society and overseas society
Presentation Type	Poster notice
Lecture Type	General
Publisher and common publisher	◎CHERNOV Mikhail, IVANOV Pavel , REGIS Jean-Francois
Date	2017/05/28
Venue (city and name of the country)	Montreux, Switzerland
Society abstract	2017 ISRS2017 Program 146
Summary	Poster Ex9With a purpose to evaluate the current status of Gamma Knife surgery (GKS) for ocular and/or extraocular intraorbital diseases in Europe, European Gamma Knife Society performed a dedicated survey.In autumn 2014 the electronic questionnaire comprising 12 questions was sent 4 times to all European Gamma Knife centers (49 as on October 2014). Responses were obtained from 20 centers (41%). Among the latter 8 centers mentioned that they do not perform GKS for ocular and/or extraocular intraorbital diseases, whereas 12 centers did it.The overall number of treated patients was>100, 30-100, and<30 in 4, 2, and 6 centers respectively. Uveal melanoma was the most common pathology treated with GKS (11 centers), followed by other ocular or extraocular intraorbital tumors. The main factors influencing decision making on application of GKS were lesion size, location, stage of disease, absence of advanced metastatic disease, proximity of the critical intraocular structures to the target, visual acuity, patient general condition and co-morbidity. Ophthalmologists were constantly involved in treatment-decision making in 10 centers. Eye immobilization technique during irradiation included invasive suturing of the rectus muscles (7 centers), retrobulbar anesthetic blocking (2 centers), and fixation on the light source (1 center); two centers did not apply eye fixation during GKS. The marginal dose depended on the tumor size and type of pathology, and frequently was at least 35 Gy (7 centers). Postradiosurgery treatment strategy included observation (8 centers), pre-planned local tumor resection (1 center), and enucleation (1 center). Second-time GKS in case of disease progression was applied in 4 centers. Marginal dose for second-time GKS was either similar to primary treatment (3 centers), or corresponded to the cumulative dose of 56-57 Gy (1 center).In conclusion, there is definite variability in indications, technique, and general treatment strategy between European Gamma Knife centers performing GKS for ocular and extraocular intraorbital pathology. Development of the optimal radiosurgical treatment strategy in such cases may be done by comparative evaluation of outcomes in collaborative multicenter studies.