PhD defence J.K.W. (Jasper) Gerritsen

Dissertation in short:

The overall aim of this thesis was to evaluate the impact of awake brain surgery in patients with glioblastoma (high-grade malignant brain tumors). The objective during glioma surgery is to resect as much of the tumor as possible while preventing inducing neurological deficits. Therefore we developed a new so-called "onco-functional outcome" to address both the oncological goal of surgery (resecting as much tumor as possible) and the functional goal (preventing neurological deficits) into one merged surgical outcome. Currently, awake surgery is usually reserved for patients with low-grade glioma, in which it is found to improve the surgical outcomes, but strong evidence in glioblastoma patients was still lacking. According to our analyses based on more than 1000 glioblastoma patients from Rotterdam, The Hague, Leuven and Boston, awake surgery works best to improve the surgical outcomes in patients who are younger, have less neurological deficits and are in better condition before the operation. In these patients, awake surgery leads to longer overall survival and progression-free survival, less neurological deterioration, and a higher extent of resection. In patients who are older, have more neurological deficits or are in suboptimal condition before the operation, awake surgery seems useful to maintain the patient's performance in order to undergo chemotherapy and radiotherapy or to prevent long-term neurological deficits. This thesis has therefore provided neurosurgeons with objective data to improve the decision making with regard to individual glioblastoma patients.