According to the American Cancer Society, the United States has one of the worlds highest rates of rectal cancer. Only prostate cancer, lung cancer, and common skin cancers occur more often.
Rectal cancer is rare in young people, with incidence rising sharply after age fifty.
The rectum is the last eight to ten inches of the colon. The exact causes of rectal cancer are unknown. Warning signs of rectal cancer include changes in bowel habits, such as constipation or diarrhea, stools that look blackish or tar-like, very dark red or bright red blood in the stool, and abdominal pain. Other symptoms include frequent gas pains, bloating, fullness or cramps, a feeling that the bowel doesn't empty completely, stools that are narrower than usual, loss of weight for unknown reasons, and constant fatigue. Call a doctor if any symptoms last more than two weeks.