I find that people that don't have anything to live for or don't believe in God have the hardest time during trials such as these. I'm not a doctor as you pointed out. But I know the health of the soul has a tendency to determine the outcome of a lot of ills.
I recently had a cousin die of brain cancer within 4 months after diagnosis. She was only 49 and had been an oncology nurse for over 25 years. She was a wonderful person who helped many people with a strong faith and a tremendously positive and selfless spirit.
Do you really believe that Molly Ivins experienced breast cancer and her disease progressed over 6-7 years to the metastatic stage because she has an unhealthy soul resulting from an ultra-liberal political point of view? What's more likely is that she was a smoker during her lifetime or she has a genetic predisposition to breast cancer and her cancer is of a type that did not respond well to standard therapies.
As someone working in the field of oncology, let me tell you that cancer kills Republicans as well as Democrats, people of faith as well as those of little faith.