Beef is red meat, which is not good for cancer patients. Not that you can't eat, but that you should eat less.
Chicken is controversial, western medicine thinks it is good, and Chinese medicine thinks hormone is not good for breast cancer.
To sum up, personally, don't eat mutton just after surgery, which is absolutely bad for the wound. The other two kinds of meat, eaten properly, should not be a big problem. During chemotherapy, because chemotherapy drugs do great harm to the stomach, try to eat some light and digestible food.