Don't let the facts stand in the way of a good story...

The graphic (thanks Nature) is a linear representation of a way to think about how tumors develop blood supplies.  It is, of course, not actually what happens, but a way of thinking.  And that way of thinking has produced lots of attempts at intervention.  Of course, the interventions are not just applied to thinking, but to bodies.  And therein lies the trouble.  Recent work (http://www.sciencedirect.com/science/article/pii/S1535610811004478) has demonstrated what was likely a fairly obvious outcome.  Very popular (meaning blockbuster) anti-angiogenic drugs have been demonstrated to slow tumor progressions.  But hypoxia (lack of oxygen) is a primary driver in cancers becoming metastatic.  So primary tumors may not grow as swiftly, but metastatic tumors appear more frequently.  Of course, that was not part of the thinking.  But again, this is a real system, a complex biological web, not a thought experiment.

I remember the almost fever pitch of effort promoting Judah Folkman (pioneer of anti-angiogenic therapy) in a poorly disguised effort to deliver a Nobel Prize to him before he died.  It generated a simple, fatally-flawed logic of how to treat cancers by denying blood supply.  So we have another of the common, killer beliefs about medicine and science.  Killer, sadly.