Anesthesia Induced Brain Cancer Survival (ABC Survival): A Feasibility Study

In Canada, cancer is the most common cause of death. Among solid organ cancers, brain tumors, depending upon type and grading, impose significant morbidity and mortality. In addition, cancer progression and recurrence is one of the most common complications in management of high-grade gliomas and among all, Glioblastoma Multiforme (GBM) is the most common and aggressive primary brain cancer. Many factors have been demonstrated to affect glioma progression . Some of the most consistently sited variables are age, grade of tumor, tumor size and location, molecular diagnosis, extent of resection, and chemotherapy and radiotherapy.

On the other hand, though, anesthesia remains an integral part of glioma surgeries, and two types of anesthetics (total intravenous agent, such as, propofol and volatile, such as sevoflurane) are commonly used during maintenance phase of general anesthesia (GA) across over all world; their effects on brain cancer progression are not yet investigated extensively. Recent studies have highlighted that there could be an association of anesthesia with cancer progression in other solid organs. Very few researches have been published demonstrating the relationship between type of anesthetic and glioma progression. One study found that exposure of glioblastoma stem cells to volatile agent (isoflurane) increased their migration capacity in vitro and increased their migration distance in vivo in animals. A second study found that exposure of glioma stem cells to sevoflurane increased tumor cell proliferation as well as tumor markers, most notably hypoxia-inducible factors (HIF), which are associated with cancer growth. Finally, a retrospective cohort study published in 2019 compared the progression free survival (PFS) of patients who underwent high-grade glioma surgery using two different types of anesthetics. They found that, for patients with low KPS, anesthesia maintenance with propofol yielded a longer PFS compared to sevoflurane (15). With this background, it seems propofol based anesthesia may limit the progression of brain cancer progression and therefore, the purpose is to evaluate type of anesthetics (propofol versus sevoflurane) as a factor responsible for glioma progression and survival characteristics. As the Investigators are planning for a future phase III study, it is imperative to understand thoroughly the details regarding feasibility, workflow, enrollment and drop out characteristics, reasons of deviation and adherence rates to anesthesia protocols and problems in follow ups. Therefore, this feasibility study is a path to a well-designed larger multicenter randomized study.