The treatment of low-grade gliomas (LGGs) continues to evolve and improve as the field of Neurosurgery incorporates progressive advances in neuroimaging, molecular and cellular pathophysiology, extraoperative and intraoperative brain mapping, intraoperative surgical adjuncts, and postsurgical treatment with radiation and chemotherapy. While as surgeons we focus primarily on the surgical treatment of LGG patients, in order to provide optimal care for our patients we need to understand all aspects of their disease process. In this issue of Neurosurgery Clinics of North America, we have assembled an international panel of experts in the LGG field to discuss the latest advances in our understanding of the epidemiology, pathophysiology, clinical aspects, and treatment of these complex tumors.
The initial articles in this issue overview the epidemiology, classification, and molecular pathogenesis of LGGs. The WHO classification (2016) of LGGs stratifies these tumors based upon mutations in isocitrate dehydrogenase (IDH) and co-deletion of chromosomes 1p and 19q into separate diagnostic and prognostic groups. IDH–wild-type astrocytomas are the most aggressive LGGs, while IDH mutant, P53/ATRX mutated astrocytic LGGs have an intermediate prognosis, and IDH mutant, 1p/19q co-deleted oligodendrogliomas generally have a less aggressive clinical course. Studying the molecular pathophysiology of LGG has provided fundamental insights into gliomagenesis and provided potential opportunities to target novel treatments to these tumors.
The pathology, clinical course, and in particular epileptogenesis seen in LGG patients depends in large part upon the many ways that these tumors invade and interact with surrounding brain tissue. These issues are examined in depth in the articles of this issue. While the possible malignant progression that occurs in LGG patients appropriately remains at the forefront of clinical care, the day-to-day quality of life experienced by our patients is in large part determined by tumor cell interactions with local neuronal, glial, and blood-brain barrier elements. These areas of brain pathophysiology and patient care will require much further study going forward.
The majority of this issue focuses on aspects of treatment of LGG patients. Several articles detail important surgical considerations, in particular, ways to increase the extent of resection of these infiltrating brain tumors. Specific topics include when and how to use low- versus high-frequency stimulation for intraoperative mapping of LGG patients; intraoperative surgical adjuncts to increase extent of resection, including intraoperative MRI, fluorescence imaging, and Raman spectroscopy; mapping “higher” brain functions, including cognition and emotion; and the evidence that greater extent of resection improves patient outcome. Articles on chemotherapy and radiation therapy for LGG summarize the latest trials in these areas. The remaining articles tackle a variety of topics of importance to neurosurgeons: how the impact of extent of resection is altered by molecular classification in LGG; supramaximal resection, neuroplasticity, and LGG screening; and the fundamentals of building a glioma clinical practice.
To care for LGG patients and advance the field further requires a multidisciplinary team of experts specializing in neuro-oncology, epilepsy neurology, neurosurgery, neuropathology, neuroradiology, neurophysiology, molecular and cellular neuroscience, neuropsychology, and rehabilitation. This issue of Neurosurgery Clinics of North America strives to update the latest information on LGG in the majority of these interrelated disciplines.
© 2018 Published by Elsevier Inc.