THERAPEUTICAL NOTE   

Journal of Neurosurgical Sciences 2018 April;62(2):214-20

DOI: 10.23736/S0390-5616.16.03547-X

Copyright © 2016 EDIZIONI MINERVA MEDICA

language: English

Combined stereotactic biopsy and stepping-source interstitial irradiation of glioblastoma multiforme

Stefanie BREHMER ¹, Christian V. GUTHIER ², Sven CLAUSEN ³, Frank SCHNEIDER ³, Dirk-Michael SCHULTE ¹, Matthias BENKER ⁴, Frederic BLUDAU ⁵, Gerhard GLATTING ⁶, Alexander MARX ⁷, Peter SCHMIEDEK ¹, Jürgen HESSER ², Frederik WENZ ³, Frank A. GIORDANO ³ ✉

¹ Department of Neurosurgery, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany; ² Experimental Radiation Oncology, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany; ³ Department of Radiation Oncology, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany; ⁴ Carl Zeiss Meditec AG, Oberkochen, Germany; ⁵ Department of Orthopedic and Trauma Surgery, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany; ⁶ Medical Radiation Physics/Radiation Protection, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany; ⁷ Department of Pathology, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany

Patients diagnosed with glioblastoma multiforme receiving stereotactic biopsy only either due to tumor localization or impaired clinical status face a devastating prognosis with very short survival times. One strategy to provide an initial cytoreductive and palliative therapy at the time of the stereotactic biopsy is interstitial irradiation through the pre-defined trajectory of the biopsy channel. We designed a novel treatment planning system and evaluated the treatment potential of a fixed-source and a stepping-source algorithm for interstitial radiosurgery on non-spherical glioblastoma in direct adjacency to risk structures. Using both setups, we show that radiation doses delivered to 100% of the gross tumor volume shifts from sub-therapeutic (10-12 Gy) to sterilizing single doses (25-30 Gy) when using the stepping source algorithm due to improved sparing of organs-at-risk. Specifically, the maximum doses at the brain stem were 100% of the PTV dose when a fixed central source and 38% when a stepping-source algorithm was used. We also demonstrated precision of intracranial target points and stability of superficial and deep trajectories using both a phantom and a body donor study. Our setup now for the first time provides a basis for a clinical proof-of-concept trial and may widen palliation options for patients with limited life expectancy that should not undergo time-consuming therapies.

KEY WORDS: Glioblastoma - Biopsy - Radiotherapy