Modulating the tumor microenvironment to improve radiotherapy.

Radiotherapy can ablate vascular tissue, but the antiangiogenic effect is counteracted by upregulation of endogenous proangiogenic signals, particularly vascular endothelial growth factor. This effect, which has long been a concern in oncology, is relevant to a discussion of radiation for the treatment of age-related macular degeneration (AMD). In oncology, a broad array of agents that target growth factors and receptors is being actively studied for the potential to enhance the activity of radiation in controlling malignancies. Progress with such combinations in oncology may be relevant to parallel strategies for treating and containing neovascularization in AMD and other retinal diseases.