For several months before my cancer diagnosis, I experienced bouts of extreme fatigue. At 58, I attributed this to the normal aging process, but at my wife’s urging, I scheduled an appointment with our family doctor. A simple blood test showed that my hemoglobin level was very low. I have a family history of anemia, so I wasn’t that surprised or concerned. After a blood transfusion, I immediately felt better.

But the fatigue came...