The cancer research and cancer epidemiology communities do not really talk to each other (as a cancer researcher for many years I have never been to an epidemiology seminar despite working in a 'cancer center'). So it is really a fight for money and mind influence. Most cancer researchers lean towards drugs targeting molecular mechanisms of cancer, cancer epidemiologists, on the other hand, aim for political decisions that combat environmental factors. Where should most money go? what should be discussed in the media?
Vogelstein proposes a simple model that explains a lot of data. Sure, the implications are bleak, but the scientists I talked to were not really surprised that it finally got out.
Iodine. Have you looked into it? The abstracts over on nih.gov are pretty interesting - google for "iodine cancer nih" without quotes. I'm curious what a cancer researcher has to say. Mostly I'm interested in weather your peer group has even looked at this.
I think it will help most if I explain the incentives for scientists (at least in the US). From their first day in the lab scientists are rewarded most for generating data and making discoveries. The more novel and paradigm shifting the discovery the better - as it opens the door to high-impact publications and future research money. But "extraordinary claims require extraordinary evidence" and the more unexpected the finding the more difficult it is to convince your peers and get it published.
Somewhat idealistically, this has two consequences for a good lead scientist:
1) hew will guide his lab to explore the unexplored
2) and subject the most novel and promising findings to the most stringent experimental verification.
So the answer to your direct question - yes probably someone somewhere tried to test the iodine-breast cancer hypothesis, but since it is not a major topic in breast cancer research the experiments have probably failed and were not published and thus independently replicated
Vogelstein proposes a simple model that explains a lot of data. Sure, the implications are bleak, but the scientists I talked to were not really surprised that it finally got out.