I have no idea how the information was formed that when you grill a piece of steak and the outside turns black that that stuff can cause cancer. It must have been found out while doing a study however I have no clue as to when and where it came from. The problem must be that the meat turns into a carcinogen when it chars and gets that black tasty stuff formed. Maybe scientist studied that heterocyclicamines (HCAs) and polycyclic aromatic hydrocarbons (PAHs) are formed from the cooking. Preparing the meat this way is supposed to make the HCA in the strongest form possible. Cancer can form in the stomach, liver, large and small intestines, and on the skin.
Should you just cut out eating grilled steaks and chops all together because of this health risk? I don’t think so but it could be a good idea. There is a way to avoid the HCA and PAH if you cook the food a bit before putting it on the grill and make sure that the heat does not get so high that it causes the charring effect. If you do that you can get a decent tasting piece of meat however it will never taste as good as it possibly could. This is alright because your health is way more important than the small amount of pleasure from this. Make sure to grill vegetables and eat as many of them as you possibly can. They are very good for you and high in fiber.