Grading of diffuse astrocytic gliomas: Broders, Kernohan, Zülch, the WHO… and Shakespeare

Excerpt

The grading of diffuse astrocytic gliomas has been a critical topic in neuro-oncology for the past century, with the field using grading to estimate prognosis, guide clinical care, and engage in clinical and experimental studies to move the discipline forward. The question of how diffuse astrocytic gliomas are most accurately graded has, in turn, been the subject of considerable debate over the years. For example, a book published in 1989 catalogued the opinions of leaders at the time in brain tumor classification and grading [2]. With respect to grading, they discussed the conceptual and practical debate between the histological/anaplasia (pioneered by Broders and then Kernohan) and clinical/biological (pioneered by Zülch and the WHO) approaches—with each side argued effectively by its respective leaders. Remarkably, it has been only 30 years since those lively discussions, and yet our insights into the biological basis of diffuse gliomas are now substantially more advanced, and we can now bring these insights to bear on the question of grading diffuse astrocytic gliomas, perhaps aligning these historical viewpoints. Moreover, we can propose steps to set the stage for a grading system that builds on the historical approaches in light of the advents of molecular typing of CNS tumors. …