Extent of Resection and Survival in Glioblastoma Multiforme

To the Editor Brown and colleagues¹ recently reported the results of a systematic review and meta-analysis of the literature that examines the association of the extent of resection with survival in glioblastoma (GBM). They concluded that compared with subtotal resection (STR), gross total resection (GTR) substantially improves overall and progression-free survival. A key point that we want to address here is that GBM almost invariably relapses at the resection margin.² As noted by Brown et al,¹ GBM is a diffusely invasive neoplasm that, even at the time of diagnosis, invades multiple lobes and both hemispheres of the brain. The glioma cell migration flow is assumed to be centrifugal, namely, from the tumor mass toward the brain parenchyma.