The etiology of carcinoma of the colon and rectum remains unclear. However, many studies have suggested a correlation between colorectal cancer and dietary factors such as excessive intake of animal fat, protein, and refined carbohydrates, and less intake of vegetable fiber. There are also a number of diseases with hereditary predisposition to colorectal cancer. Those are familial adenomatous polyposis (FAP), hereditary non-polyposis colorectal cancer (HNPCC), Peutz Jeghers syndrome, and juvenile polyposis.

The clinical features of colorectal cancer are varied and nonspecific. The symptoms that most often prompt patients to seek medical attention include rectal bleeding, a change in bowel habit, and abdominal pain. Whether a patient has any noticeable symptoms or what form the symptoms take depends somewhat on the location of the tumor and the extent of disease.