Most patients with solid epithelial cancers, those that develop on free surfaces or linings inside the body, die because of the distant spread of tumors-metastasis. After that spread, a cure is more difficult than if the tumors were detected early or locally. Tumors develop a new supply of blood. Traditional anticancer therapies have had the goal of causing a decline in the tumor. Yet by focusing on the tumor's blood supply, microscopic differences between tumors and clonal differences within tumors may be avoided. Doing so may overcome tumor resistance to treatment and may result in treatments that can be more universally applied across tumor types.