DOCTORS HAVE COME a long way since the days when cancer treatments consisted of arsenic paste or ground-up toads. Most of that progress has taken place during the last sixty years. Because of progress in treatment as well as early detection, the overall cure rate for cancer has gone from 38 percent in the 1960s to 50 percent today. People are usually considered to be cured of cancer if they survive for five years without a return of the disease.

The three main ways of treating cancer are surgery, radiation, and chemotherapy (treatment with drugs). The type of treatment a doctor chooses will depend on the kind of cancer a person has and how advanced the disease is—whether it has spread to more than one part of the body, for instance. The effects of the treatment will depend largely on...