Brain tumor incidence and outcome

Malignant gliomas, including the anaplastic astrocytoma (AA) and glioblastoma multiforme (GBM), are the most common primary brain tumors, and occur at a rate of approximately 6.08/100,000 individuals annually within the US, an annual incidence of 17,500 cases (CBTRUS, 2000). Current treatment options include surgery, radiation therapy (RT) and chemotherapy. Unfortunately, prognosis remains extremely poor and the median survival of 12 months for GBM has not changed appreciably over the last several decades (Walker et al., 1980). Limitations to therapy include both the infiltrative nature and prominent angiogenesis of AA and GBM.

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 (Mikkelsen and Edvardsen, 1995; Mikkelsen and Rosenblum, 1995). Regional infiltration during tumor progression has been most strikingly shown in the whole-mount studies of Scherer and Burger (Scherer, 1940; Giangasporo and Berger, 1983; Burger and Kleihues, 1989), 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 (WM) 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 (Burger et al., 1983; Daumas-Duport et al., 1987). 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 (Hochberg and Pruitt, 1980; Bashir et al., 1988).