Every doctor recognizes them.
The man who discovers a bruise on his thigh and becomes convinced that it is leukemia. The woman who examines her breasts so frequently that she makes them tender, then decides that the soreness means she has cancer. The man who has suffered from heartburn all his life but after reading about esophageal cancer has no question that he has it.
They make frequent doctors' appointments, demand unnecessary tests and can drive their friends and relatives -- not to mention their physicians -- to distraction with a seemingly endless search for reassurance. By some estimates, they may be responsible for 10 to 20 percent of the nation's staggering annual health care costs.