COLON CANCER

Colon, or colorectal, cancer is cancer that starts in the large intestine (colon) or the rectum (end of the colon).
Other types of cancer can affect the colon, such as lymphoma, carcinoid tumors,melanoma, and sarcomas. These are rare. In this article, use of the term "colon cancer" refers to colon carcinoma only.

Colon cancer is cancer that occurs in the cells of the colon.

Colon Cancer Symptoms

It is common to have colon or rectal cancer without symptoms. Many patients are free of symptoms until their tumors are quite advanced.

Symptoms associated with colorectal cancer include may also be caused by other conditions. These symptoms include:

• Changes in bowel movements, such as diarrhea or constipation, or change in consistency of stools
• Feeling that the bowel has not emptied completely after a bowel movement
• Abdominal discomfort such as gas, bloating, and cramps
• Rectal bleeding or blood in stool
• Unexplained weight loss
• Unexplained iron-deficiency anemia (low red blood cell count)
• Weakness and fatigue

Diagnosis

• Barium enema, also known as a lower gastrointestinal series, takes X-rays of the large intestines.
  
• Biopsy is a test in which a small amount of tissue from the suspected area is removed for examination by a pathologist to make a diagnosis.
  
• Colonoscopy is performed to see inside the rectum and the entire colon and remove polyps or other abnormal tissue for examination under a microscope. In addition to the standard colonoscopy, UCSF Medical Center offers a virtual colonoscopy.
  
• Digital rectal exam involves the doctor or nurse inserting a gloved, lubricated finger into the rectum to feel for any abnormalities.
  
• Fecal occult blood test is a test for blood in the stool. Such blood may arise from anywhere along the digestive tract. Hidden blood in the stool is often the first, and in many cases the only, warning sign that a person has colorectal disease, including colon cancer.
  
• Polypectomy is performed during a sigmoidoscopy or colonoscopy to remove polyps.
  
• Sigmoidoscopy is performed to see inside the rectum and the lower colon and remove polyps or other abnormal tissue for examination under a microscope.