If there are symptoms, the following may indicate colon cancer: 1  Abdominal pain and tenderness in the lower abdomen. 2  Blood in the stool. 3  Diarrhea, constipation, or other change in bowel habits. 4  Narrow stools. 5  Weight loss with no known reason.
Diarrhea may be caused by: lactose intolerance. bacterial infection. damage to intestinal wall. hormone-producing tumors (including certain types of pancreatic neuroendocrine tumors) inflammation or ulceration of the bowel. malabsorption caused by surgery that has shortened the intestines. pancreatic enzyme insufficiency.
Diarrhea may be caused by a temporary problem, like an infection, or a chronic problem, like an intestinal disorder or disease such as IBS or Crohn's. A few of the more common causes of diarrhea are: Bacterial infections. Several types of bacteria, consumed through contaminated food or water, can cause diarrhea.