Brain tumor incidence and outcome

Malignant gliomas, including the anaplastic astrocytoma and glioblastoma multiforme, are the most common primary brain tumors, occurring at a rate of approximately 6.08/100 000 individuals annually within the USA, an annual incidence of 17 500 cases.[1] Current treatment options include surgery, radiation therapy, and chemotherapy. Unfortunately, prognosis remains extremely poor and the median survival of 12 months for glioblastoma multiforme has not changed appreciably since the 1980s.[2] Limitations to therapy include both the infiltrative nature and the prominent angiogenesis of anaplastic astrocytoma and glioblastoma multiforme.

Pathological patterns of infiltration of peritumoral brain

Gliomas in general, and gliomas that are more anaplastic in particular, infiltrate and spread great distances in the brain.[3,4] Regional infiltration during tumor progression has been most strikingly shown in the whole-mount studies of Scherer and Burger,[5–7] where glioblastomas have a central area of necrosis, a highly vascularized cellular rim of tumor, and a peripheral zone of infiltrating cells. Infiltration occurs along white matter tracts, around nerve cells, beneath the pia, and, prominently, along angiogenic blood vessels. Studies have shown that tumor cells have migrated from the primary site of malignant gliomas, resulting in the almost inevitable local recurrence and tumor progression seen clinically.[8,9] Recurrence of human gliomas following surgery and radiation is most commonly seen in the margin adjacent to the initial tumor, where leaking tumor neovasculature is permeable to imaging contrast agents, but may also be remote.[10,11] Angiogenesis is quantitatively most prominent in glioblastoma compared with malignancies elsewhere in the body,[12] and the patterns of growth of invading glioma and angio/vasculogenesis suggest that these processes are fundamentally related.