Glioma Recurrence following Surgery: Peritumoral or Perilesional?

In comparison to other cancers, gliomas are locally invasive cancers that seldom metastasize. Glioma cells infiltrate brain parenchyma up to several centimeters from the tumor core. Therefore, their recurrence occurs at the margin of tumor resection in about 90% of patients (1). Significant effort is put into analyzing peritumoral regions to understand the mechanisms of glioma recurrence after surgery (1–4). Such studies are done on peritumoral biopsies collected either before or during surgery. This comment seems incidental but is critical.