Possible signs of cancer of the colon and/or rectum include a change in bowel habits or blood in the stool. These and other symptoms may be caused by colon and/or rectum cancer. Other conditions may cause the same symptoms. A doctor should be consulted if any of the following problems occur:
- A change in bowel habits
- Blood (either bright red or very dark) in the stool
- Diarrhea, constipation, or feeling that the bowel does not empty completely
- Stools that are narrower than usual
- Frequent gas pains, bloating, fullness, or cramps
- Weight loss for no known reason
- Feeling very tired
- Vomiting