Patients

For this prospective study we included 23 patients (median age 66 years, range 41–84 years), who underwent surgery at the department of neurosurgery between 2012 and 2014. The local ethics committee of the University of Freiburg approved data evaluation, imaging procedures and experimental design (protocol 100020/09 and 5565/15). The methods were carried out in accordance with the approved guidelines. Written informed consent was obtained from all patients.

Inclusion criteria were: (1) age older than 18 years, (2) preoperative MRI with H-MRS, (3) intraoperative MRI-guided sampling of tumour tissue from contrast-enhancing tumour, (4) histopathological confirmation of a glioblastoma multiforme (WHO criteria) (5) three and six-months follow-up with contrast-enhanced MRI. From those 23 patients, 20 patients could be enrolled into this study (Supplementary Table 1), 3 patients had insufficient follow-up. Progression-free survival (PFS) and overall survival (OS) was available for 18 patients. Two patients had no tumour progression until the end of 2015, and 7 patients had outstanding overall survival (OS) and are still alive. The Kaplan-Meier method was used to provide median point estimates and time-specific rates. The Hazard-Ratio (HR) was calculated by Cox-Regressions tests.