Anti-angiogenics and radiation therapy

Investigation of the combined effects of radiation and anti-angiogenic therapy has yielded intriguing preclinical and clinical results. The cytotoxic effects of radiation on cancer cells are critically dependent on the formation of free radicals and therefore an adequate supply of oxygen by blood vessels. Most tumors, however, are characterized by irregular angiogenesis and marked hypoxia. Anti-angiogenic therapy could contribute to a normalization of blood vessels to improve blood flow, alleviate hypoxia, and subsequently increase the effectiveness of radiotherapy. Clinical evidence in glioblastoma and other tumor entities has shown encouraging outcomes and warrants further characterization of the synergism between these therapies. Care should be taken with respect to the toxicity profiles of both entities, especially where side effects overlap, for example, damage to organs such as the liver, kidney, or the lung; ischemic complications; organ perforation; and the impairment of bone marrow.