Early Stereotactic Gamma Knife Radiosurgery to Residual Tumor After Surgery of Newly Diagnosed Glioblastoma

Glioblastomas are highly malignant brain tumors that recur about 6 months after treatment. Most recurrences develop at the edge of the surgical margin and a common reason for an early recurrence of a glioblastoma is when tumors are not completely resected. This may be the case when intraoperative neuro-monitoring indicates that further resection would impair certain motor functions. Physicians can identify residual tumor in early (24-72h after surgery) postoperative MRI scans and could treat these regions. However, this treatment would not be a part of the recommended standard of care and thus, any further treatment of this areas will need a clinical trial. The aim of this trial is to evaluate if the use of another modality to deplete these areas of residual tumor identified in early postoperative MRI scans will provide a relevant benefit in terms of progression-free survival (which means a prolongation of the time that patients do not experience a re-growth of the tumor). The modality is termed "radiosurgery", which is a non-invasive technique to delete cells without using a blade but a highly focused beam of gamma rays. The machine that focusses these rays (like a magnifying glass that can focus light), is called 'gamma knife'. Gamma knife radiosurgery is a safe and effective treatment for a plethora of malignant and benign brain tumors and the technique is used since the 1950s and there has been a continuous improvement of precision and patient comfort up to now.