Early Detection for Cancer Is a Risky Business
Accepting an examination of your body parts in an effort to find cancer earlier means you are willing to risk your life today for the theoretical possibility that you will gain extra years in the distant future.
For example, I have known perfectly healthy people in their forties suffer a perforation of their bowel during a routine colonoscopy and die—all from an effort to prevent colon cancer in their sixties or seventies.
While attempting to prevent one death from colon cancer with 1,000 examinations, two people may suffer from this potentially fatal complication (in addition to other complications, such as those from bleeding and anesthesia). Fortunately, similar cancer benefits can be had with a safer sigmoidoscopy examination, at almost no risk, or a test of the stool for blood or DNA at no risk of physical harm.
Screening for cancer is "disease mongering" at its worst. By casting a large net with early detection schemes, people are roped into laboratory tests, imaging, doctors' office visits, biopsies, surgeries, radiation treatments, pharmaceuticals, chemotherapies, and hospitalizations. Disease mongering turns people into patients, and few will benefit.