No one wants to get cancer but if your going to get a cancer then colon cancer is one of the ones to get.  Colon cancer is a curable disease, but the key to cure is early diagnosis and treatment.  Unnecessary delays can result in distant seeding (metastasis) of the cancer to other organs in the body.  Once the cancer has metastasized, depending upon whereto, a cure may no longer be possible.  Even chemo and radiation therapy may not be able to halt further spread of the disease.  

It is important for doctors to recognize the signs and symptoms of colon cancer and respond appropriately with standard diagnostic tests and x-rays. A persistent change in bowel habits, blood in stool, anemia, malaise, can all be signs of early colon cancer and should prompt further investigation.  One of the ways colon cancer is discover is by special x-rays known as double contrast barium studies.  This is also one of the ways colon cancers are missed.  For whatever reasons sometimes radiologist do not see what is clearly present on a film, and then the other doctors rely upon the radiologist's mistake.