Chemotherapy of brain tumors

Abstract

✓ The uptake and distribution in brain tumors of a parenterally administered chemotherapeutic agent were studied in mice bearing intracerebral implants of a transplantable ependymoblastoma. Tritiated methotrexate (3H-MTX) was injected intravenously, and autoradiographs of the tumors and adjacent brain were prepared at 2, 10, and 60 min after injection using a technique suitable for soluble compounds. In the tumors at 2 min the drug was mainly intravascular and interstitial while at 60 min the drug was mainly intracellular. This is the first demonstration of cellular uptake of a chemotherapeutic agent by neoplastic cells within the brain. At 60 min, almost all the cells in the central mass of the intracerebral tumors were heavily labeled. However, cells at the periphery of the mass and those infiltrating into adjacent brain showed scanty labeling. Uptake in normal brain was very low, while uptake in edematous brain adjacent to the tumors was much higher although not as high as in the tumors. The study shows that this chemotherapeutic agent is capable of penetrating into the neoplastic cells of an intracerebral tumor following parenteral administration, but that the degree of penetration varies considerably depending on the location of the cells within the brain.