Colorectal carcinoma is a cancer, or malignant tumor, of the large intestine, which may affect the colon or rectum.

Signs and symptoms of colon cancer include:

• A persistent change in your bowel habits, including diarrhea or constipation or a change in the consistency of your stool
• Rectal bleeding or blood in your stool
• Persistent abdominal discomfort, such as cramps, gas or pain
• A feeling that your bowel doesn’t empty completely
• Weakness or fatigue
• Unexplained weight loss