Surgical decision making in the era of supramarginal glioma resections: a current perspective and narrative review

Whether to surgically resect a margin of grossly normal appearing brain around anatomically amenable diffuse gliomas (i.e., perform a supratotal, supramarginal, or supramaximal resection) has been controversial. Over the past 5-10 years, however, evidence published by multiple independent groups has established a substantial survival benefit to this approach, moving the field towards a consensus that supramarginal resections should be offered when possible. However, many practitioners remain hesitant to offer supratotal resections due to concerns for variable neuropsychological outcomes and a mindset of "first, do no harm." Unfortunately, and perhaps counterintuitively, available data also suggest that opting for more conservative surgical approaches when more aggressive resections are possible may result in both suboptimal long-term functional and survival outcomes. To explore this complex and actively evolving issue, here I review evidence surrounding the multidimensional clinical impacts of supramarginal resections across all diffuse glioma subtypes. I then evaluate what is known about anatomical-functional relationships subserving cognition, behavior, and mood regulation, and I examine ethical considerations that arise when counseling patients at the difficult time of diagnosis. I then conclude with a set of case examples that demonstrate how the principles explored in this review can be applied in real-world situations to optimize, individualize, and humanize oncological and functional outcomes.