Don't expect doctors to have the answers. They speak in carefully guarded probabilities.
Don't expect doctors to necessarily have your quality of life foremost in their minds. When they say "it would be easiest to do X", ask them whether it's easiest for you the patient or them the doctor. Similarly, "it would be best" ... for whom?
Find a cancer support group and talk to them. Find your local branch of the Cancer Society and talk to them. These folks can give you emotional perspectives that you can't get from doctors. (e.g., "What's it like to have only one breast?").
Double-check every medication you're given to see whether it interacts with your others. One of my relatives is constantly catching doctors attempting to prescribe dangerous cocktails. "Oh yeah, you're right. Try this one instead," they'll say.
Read up on side-effects from medication and be vigilant. Again, relative kicked cancer without blinking, but the complications of treatment nearly killed her, and drugs damaged her liver, gave her a heart attack, and brought on diabetes.
--Nat
Just because they have an MD, Ph.d. behind the name doesn't make them miracle workers. Hospitals are horribly understaffed and what staff there is available are overworked to the point of making stupid mistakes. Medicine isn't a right to life but merely a possibility at cheating death a little while longer. There are no guarantees in this lifetime so why should medicine be any different?
I don't know which was worse; watching my father die of esophageal cancer or my mother's helplessness to save him after years of dispensing medical service to others. Cancer is always harder on those nearest to the patient since the patient has no other choice but to prepare for the inevitable. Be happy, she's alive.