I have been told by my cancer navigator that walking is one of the best forms of excercise and is proven to prevent recurrent cancer. This can be done at your own pace but just get out and walk. You definately don't want to do any type of extreme physical activity like running, aerobics or anything like that.
I'm sorry you have had so many surgeries! Talk to your Physical Therapist about it also! I'm praying for you!