Disclosed are methods of selectively reducing the blood supply to a neoplastic region, such as a tumor region, thereby selectively causing necrosis of the neoplastic tissue without substantial necrosis of adjoining tissues. In particular, methods are disclosed of selectively reducing the blood supply to a neoplastic region, such as a tumor region, by causing selectively occlusion of blood vessels feeding the neoplastic region. The invention also provides methods of selectively causing anti-angiogenic action in a neoplastic region, such as a tumor region, with the result that new blood vessels are not formed to sustain the neoplasia. The methods employ intra-arterial injection of polyunsaturated fatty acids, preferably in the form of salts, preferably with a lymphographic agent, and optionally with an anti-cancer drug, and/or a cytokine. The invention also provides solutions of PUFAs, or salts of PUFAs, in combination with a lymphographic agent.