When I was little, before I get into biological studying, I read a news talking about cancer would be totally cured after decades. I still remember that researchers had a theory to claim if they could limit the blood vessel generation near to tumor, then the rapidly growing cancer cell couldn't get enough nutrients and would kill them. However, this theory seems not to work well. Cancer cells or tumor still have another way to get enough nutrients to live, or at least, maintain themselves to survive and endanger the host. So, my question is how can rapid growth cancer get nutrients without blood vessels in vivo?
Long back in 1971 Falkman and others put forward new therapeutic implications of targeting blood vessels supplying nutrients to tumors. Treatment you are mentioning is called 'Anti-angiogenic therapy '. However current challenges in this therapy are resistance to antiangiogenic agents and non specificity. Plus there was huge 'normalization effect' which was actually helping other blood vessels around tumor. To answer your question, Cancer cell makes their own blood vessels instead relying on host machinery. There are many other factors also why this kind of treatment is not successful yet.