Your situation sounds more like a philosophical one rather than a medical one. Doctors (in this case, specifically Oncologists) are professionals who treat cancer with chemo and radiation. Skepticism about those treatments is not a reflection on Oncologist's ability to design and administer those treatment plans any more than the ability of an auto mechanic to fix a car, whether or not you are skeptical about the benefits of a car. I don't put faith in either one of them, I merely hire them to do the job they are trained to do.
In my opinion, faith is more of a factor in "miracle cures" since there are no studies, clinical trials, or regulation to substantiate their claims.