You have to be careful with fruit juices. Too much fructose even in healthy people is not good - making the body acidic among other things.
You can OD on fructose quickly if you're juicing fruits. I always make smoothies with fruit instead of juicing them since it keeps the pulp and I can add in protein powder and other things that somewhat offset the sweatness.
If you had cancer you should avoid anything sweet as cancer feeds of it. But since your health is out of whack anyway lowering the amount of sweets (even if fresh fruit) and carbs in your diet will be helpful I'm sure.