1%: Personal knowledge spread a bit everywhere. You will certainly find similar data if you look for the relation between cancer and meat consumption, or lack of cancer and vegetarianism. That is repeated in TV documentaries from time to time and is very old knowledge. Adolf Hitler (there! ) was vegetarian and abstemious because he had fear of getting cancer. Maybe you'll find statistics saying 2% or 3%. You get the point. Vegetarians "don't" get cancer and substances in meat (putrescina and cadaverina, in Italian, are those I remember) are not good for you and I presume are also implicated in cancer. Besides, animal fat cooked at high temperature is carcinogenic etc. (some grills, now, are made in such a way that the fat dripping from the meat does not fall on the flame to come back as toxic fume to the meat). You'll certainly find many studies about that.
Cadmium: it's the "can" which releases cadmium. That's why lately there is a widespread recourse to "white inside" cans. "White inside" cans have a film of something which should not release harmful substances. In general, metal packages release metal particles. Only glass is really inert. Regular fish fished in nature doesn't contain Cadmium, only Mercury
Many packages, as you know, deliver substances to the food. For instance PET bottles deliver phthalates (said to cause impotence). Well, cans are said to deliver Cadmium. There are norms which dictate how much is not too much. I personally drink glass-bottled water.
Hitler was a vegan? No wonder he was crazy.