It's hard to get people to feel optimistic about cancer, with good reason. It remains the most feared diagnosis in medicine, and fear is a powerful force, all the more so when it contains irrationality. If you ask women, for example, which disorder they are more anxious about, breast cancer or heart disease, there's little doubt what the answer would be. But fear is a very bad guide to reality. Out of total deaths among American women each year, breast cancer accounts for 1 in 31, while deaths from heart disease are 1 in 3.