health

The cause of most cases of colorectal cancer is the change in normally
benign intestinal polyps to cancerous tumors. There are several different
types of intestinal polyps, but only two carry a risk of developing into
cancers. These two types can be removed during screening tests for colorectal
cancer. The triggers that cause some polyps to become cancerous are
not completely understood.

In addition to changes in bowel habits, abdominal cramping, and
signs of intestinal blockage, patients with colorectal cancer may have the
following symptoms:

• General tiredness, unexplained weight loss, and lack of appetite
  
• Bleeding from the rectum or blood or mucus on the stools
  
• Anemia
  
• Pain when passing a bowel movement
  
• Nausea and vomiting
  
• A feeling that the bowel hasn’t completely emptied following a
  bowel movement