I believe that AN's do have some blood supply, but not as much as other types of tumors. One reason surgery sometimes is able to leave nerves intact, but the nerves stop working anyway, is because removing the AN disrupts the blood flow in the area, reducing the supply to the nerve.
One mode of radiation does have to do with scarring up the blood vessels, but it also works by creating free radicals in the tissue that cause damage to DNA and other cell structures. The disruption leads to shutting down of normal cell growth and division processes, halting the growth of the tumor. That's the story I got from one oncology intern doing a physical on me at Stanford, anyway.
Given the slow growth rate of typical ANs, I doubt that anti-angiogenic drugs will become a major factor in controlling them, but you never know...
Steve