Leksell Gamma Knife Icon in Russia Moscow Gamma Knife Center experience Valery KOSTJUCHENKO 1 (Moscow, RUSSIA), Irina BANNIKOVA 2, Alexandra DALECHINA 1, Andrey GOLANOV 1,3, Sergey BANOV 1,3, Angelika ARTEMENKOVA 1,4, Ivan OSINOV 1 Andrey Golanov 1, Ivan Osinov 2, Valery Kostyuchenko 2, Sergey Banov 2, Aleksandr Savateev 2, Anjelika Artemenkova 2, Aleksandra Dalechina 2 1 Stereotactic Radiotherapy and Radiosurgery, Moscow Gamma Knife Center, Burdenko Neurosurgical Institute, Moscow, Russia, 2 Moscow Gamma Knife Center, Moscow, Russia. 2019

Moscow Gamma Knife Center over 15 years experience From 2005 to 2012 over 1800 pts From 2012 to 2018 over 3600 pts From 2018 to present day over 800 pts for 1 year

LGK Icon new unit, new workflow, new opportunities Hypofractionated stereotactic radiation therapy -Lager tumors > 3,5 cm -Tumors near by critical structure -Treatment for 3 to 7 fractions -Low dose on brain tissue -CBCT plan correction -HDMM verifying patient movements Frame-less radiosurgery -Patient decision -Large postoperative skull defects -Small tumors without contact of the critical structure -Stereotactic CBCT -HDMM verifying patient movements

Hypofractionated stereotactic radiation therapy on the Gamma Knife Icon (HSRT) 84 pts (including 13 children) were treated HSRT on LGK icon Median age is 48.7 yr old (range: 5-74) Meningioma Grade I – 30% Metastasis – 15% Craniopharyngioma – 13% Schwannoma – 11% LGG – 5% HGG – 5% Ependymoma Grade III – 7% Other benign tumors – 3% Other malignant tumors – 4 %

HSRT for meningioma Grade I 26 pts with meningioma 3 fr х 6 Gy – 7 pts 5 fr x 5 Gy – 19 pts Median tumor volume 10,3 cm3 (range 0,7 – 18,3 cm3). Treatment time range17 to 79 min. HDMM range to 2,0 mm (median 1,5 mm) No margin Meningioma Grade I – 18,3 cm3 5 fr x 5,0 Gy 6m f-up

13 pts with brain mets. 3 fr х 7,5 – 8,0 Gy – 8 pts 5 fr х 6,0 – 7,0 Gy – 3 pts 7 fr х 4,3 Gy – 2 pts (retina mts) Median tumor volume 7,6 cm3 (range 0,3 – 21,0 cm3). Treatment time range 25 to 60 min. HDMM range – 1,0 to 1,5 mm (median 1,5 mm) Margin – 0,5 – 1,0 mm for cystic tumors and tumors beds HSRT for brain metastasis Recurrence in tumor bed after surgery (mts lung cancer) HSRT 5 fr x 6,0 Gy (40% p.i.) Volume 21,0 cm3 (no margin) 9m f-up

HSRT for retina metastasis 9 Gy isodose line on lens Metastasis of breast cancer in retina OS – 0,6 n/c 7 fr х 4,3 Gy (61% p.i.)

HSRT for brain metastasis HSRT for 2 mts of lung cancer ? (verification not available) 5 fr х 6,0 Gy thalamus V – 11,3 cm3 5 fr x 7,0 Gy frontal lobe V – 7,0 cm3 Margin – 0,5 mm 9 month f-up no ARE reduce mts volume verification primal tumor by VTS patient get target therapy no extra cranial progression

11 pts with craniopharyngiomas (10 children, 6 – 11 years old) 5 fr x 5,0 – 5,5 Gy – 11 pts Median tumor volume 2,8 cm3 (range 0,2 – 9,0 cm3). Treatment time range 35 – 55 min. HDMM range – 0,8 to 1,5 mm (median 1,0 mm) No margins. HSRT for craniopharyngiomas HSRT - 5 fr х 5,5 Gy for residual tumor 3 month after surgery (11 y.o.)

9 pts with vestibular and 1 pts facial schwannomas 5 fr x 4,0 - 4,5 Gy – 9 pts Median tumor volume 14,9 cm3 (range 4,4 – 22,2 cm3). Treatment time range min. HDMM range – 1,5 mm No margins. HSRT for schwannomas HSRT - 5 fr х 4,5 Gy for recurrence of vestibular schwannoma (volume 22,2 cm3) 6 m f-up

HSRT for recurrence of HGG 5 pts with recurrence of HGG were treated (glioblastoma – 4 pts, astrocytoma -1 pt) 3 fr х 8,5 Gy – 1 pts 5 fr x 6,5 – 7,5 - 3 pts Median tumor volume 20,4 cm3 (range 3,0 – 35,1 cm3). Treatment time range min. HDMM range – 1,5 - 2,0 mm Margins 1,0 – 2,0 mm. GBM (IDH1"-", MGMT"_", ATRX"+", MAP2"+", EGFR"+", Ki67 > 60%). Surgery ( ), chemoradiotherapy TMZ ( ) 60 Gy, Cht TMZ. Local recurrence 11 month after surgery. HSRT - 3 fr х 8,5 Gy for recurrence of GBM (volume 35,1 cm3)

LGK Icon Frame-less radiosurgery 13 pts were treated by the Frame-less radiosurgery Meningioma Grade I – 7 pts Meningioma Grade III – 1 pt Schwannoma – 1 pt Ependymoma Grade III – 1 pt Metastasis – 1 pt Medulloblastoma mts – 1 pt PD – 12 – 24 Gy 40-60% isodose Median tumor volume 1,2 cm3 (range 0,7 – 7,9 cm3). Treatment time range 17 – 50 min. HDMM range – 0,4 – 0,8 mm Margins – 0,8 - 1,0 mm.

Conclusion Moscow Gamma Knife center have first experience of using LGK Icon unit in Russia. Application of techniques HSRT and Frame-less RS allows to increase number of treated patients on 10%. Application of techniques HSRT and Frame-less RS requires careful selection of patients. Thank you for attention!