First of all I would not change your entire metabolism based on one film.  If this film was sponsored by the vegan/vegetarian group, you can rest assured that their information and logic is biased and flawed.  There is absolutely no doubt in my mind that cancer is caused by insulin elevation and carbohydrates.  Vegan diets are high in carbs.  The way I answer your concerns is the following:
If we stack up the risk of a high carb diet which is counter to your basic metabolism and carbs are drugs just like anything else with the most severe chronic disease side effects, against the potential risk from the additives in the meat industry, carbs are a 1000% more toxic than anything you could come up with in the meat.  For that reason, the first move is to go low carb high fat, then if you want to correct what you are worried about, then you can buy grass fed animals for meat.  These farms are everywhere now.  An additional thought has to do with the positive changes in liver function like the immune system with the ketogenic diet.  The liver in the proper metabolic setting will be much more capable of handling toxic insults.
The vegan / vegetarian approach is absolutely the worst diet you can pursue.  Because it lacks essential amino acids and fatty acids, your body has to digest itself for building blocks necessary for repair.  For example, if your brain cell needs repair, you might have to digest a muscle cell to get the building blocks necessary.  These diets are virtually all low calorie, so not only are you deficient in life sustaining components, you are also starving causing severe physiologic stress.  If you talk with any ninety plus year old, you will find that they ate large amounts of meats, eggs and dairy off the shelf in the grocery.  Food for thought!
Michael D. Fox, MD
Jacksonville Center
Reproductive Medicine