Ask anyone with cancer and they will tell you the cancer part never really ever goes away. You can think, and dream, and ponder, and hope, and do anything you want. You get slashed, burned, and poisoned (surgery, radiation, and chemo) and deal with baldness, nausea, fatigue, weight gain, and more. You get countless scans, blood tests, and millions of doctors.
But it still hangs there in the background to wake you up in the middle of the night with the little 'what ifs'. Those cause the stress that does all sorts of bad things to your body (that might even cause the cancer to come back). And might cause overeating which causes weight gain (which might also cause the cancer to come back.)
You can also go to therapists and support groups and they give you advice on how to deal with your emotions, your feelings, and your fears. They have such great suggestions (my personal favorite is when they told me to avoid fatigue by putting on a terry cloth robe instead of toweling off to save the extra exertion.)
My cynical side often comes out when I am dealing with the cancer things. I am also waiting for that supposed cure that is getting closer and closer every day.