Classification of Brain Tumors and Corresponding Treatments

Abstract

The first systematic classification system for brain tumors according to their presumed cells of origin was established by Cushing and Bailey in 1926. The World Health Organisation established an international tumor classification system in 1957 in order to initiate a classification and grading system with worldwide acceptance and usage since without such a system and the clearly defind histopathological and clinical diagnostic criteria it was not possible to conduct epidemiological studies and clinical trials beyond institutional and national boundaries. For brain tumors the initial classification was established in 1979 by Zülch and revised in 1993 by Kleihues with the introduction of immunohistochemistry. The third edition was published 2000, the so-called WHO blue book not only described and graded all brain tumors in precision, but also epidemiological, clinical, imaging and genetic information was presented in a structured fashion [3]. Currently the fourth edition of the WHO classification of tumors of the central nervous system, published in 2007 lists new entities and histological variants [4]. Despite of the WHO system brain tumors in general can be divided into axial and extra-axial lesions (i.e. meningioma vs. glioma) or into primary cerebral (gliomas) and secondary cerebral (metastases).