A method is provided for treatment of disorders involving hyperproliferative cells, such as malignancies, advanced stage solid tumors like glioblastoma multiforme, and non-malignant hyperproliferative pathological conditions such as adult macular degeneration. A short range, unselective cell killing radiotherapeutic substance is administered, optionally in a spatially defined volume of tissue, optionally in combination with a mitogenic agent that stimulates or induces DNA biosynthesis. In this way, the percentage of hyperproliferative that are susceptible to killing by the radiotherapeutic agent is increased. Cancer stem cells can be induced to enter S phase with the mitogenic agent, then killed with the radiotherapeutic agent. Thus, not only does the combination effectively kill the transit amplifying cell population, the most rapidly replicating type of cell in a tumor, but it also effectively kills the tumor stem cells, which give rise to the transit amplifying cells, for a longer lasting anticancer effect.