American Medical Association Family Medical Guide - American Medical Association [505]
Symptoms
The symptoms of colon cancer depend on the site of the cancer and on its stage (see page 777). Because the inside of the intestine does not have pain sensors, you won’t feel pain in the early stages of colon cancer. The first symptom is usually a change in normal bowel movements, such as constipation, diarrhea, narrow stool, or a feeling that the rectum is not completely empty. Other symptoms can include abdominal discomfort, a bloated feeling, nausea, digestive noises such as rumbling or gurgling, weight loss, blood in the stool, or bleeding from the rectum. In rare cases, a person has no symptoms at all until the cancer causes an intestinal obstruction or until the intestine ruptures and causes peritonitis.
Screening Tests to Detect Colon Cancer
Colonoscopy is the most effective screening test for colon cancer. For people who have a family history of colon cancer, the test is recommended at regular intervals beginning when they are 10 years younger than the age at which a first-degree relative (parent, sibling, or child) was diagnosed. For other people, colonoscopy is recommended every 10 years beginning at age 50, together with annual fecal occult blood tests (see page 142).
Diagnosis
If you have symptoms of colon cancer, your doctor will perform a physical examination, including a digital rectal examination (see page 144). During the digital examination, your doctor will take a sample of stool to test it for blood. He or she will recommend that you have a diagnostic test called colonoscopy to examine your large intestine. If just the lower third of the large intestine is examined, the procedure is called sigmoidoscopy (see page 144). Your doctor also may order a barium X-ray (see page 767) of your large intestine.
Colectomy, Colostomy, and Ileostomy
To treat intestinal disorders such as diverticulitis, ulcerative colitis, and cancer of the large intestine (colon), it may be necessary to remove all or part of an intestine in a procedure called colectomy. If possible, the two severed ends of the colon are sewn or stapled together to maintain a passageway for stool. When it is not possible to maintain this passageway, an opening called a stoma is made in the abdominal wall, through which stool can pass into a bag. The procedure is called a colostomy when the colon opens through the stoma and an ileostomy when the small intestine opens through the stoma.
A colectomy is surgical removal of part or all of the colon. In a partial colectomy, the diseased part of the colon is removed and the two severed ends of the colon are joined together. The surgeon makes a temporary or permanent opening called a colostomy to allow stool to pass directly outside the body through an artificial opening in the abdominal wall (instead of the normal route through the large intestine and rectum). If the colostomy is temporary, the stoma will be closed after the surgically severed ends of the colon heal and fuse together.
In a total colectomy, which is sometimes done for inflammatory bowel disease (see page 764), the entire colon is removed. The rectum may or may not be removed. If the rectum is removed, the doctor may perform an ileostomy.
Colostomy and ileostomy In a colostomy, a surgeon creates an artificial connection between the interior passageway of the colon and the outside of the body. In an ileostomy, the artificial connection is between the ileum of the small intestine and the outside of the body. The surgically created opening is called a stoma.
Partial colectomy with a colostomy
In a partial