Do I Have Bowel Cancer?

Bowel, or colorectal cancer develops in the large intestine (colon and rectum.) It is the third most commonly diagnosed cancer. Bowel cancer is slow to develop and may exist for years before diagnosis. However, because it is normally nonaggressive in its development, prevention and regular screening can insure that malignancies are caught early, or even prevented.

Bowel cancer often develops from adenomatous polyps. These button or mushroom shaped growths arise from the cells lining the large intestine. Adenomatous polyps are usually benign, but if not removed often become cancerous. Untreated bowel cancer can erode through the lining of the intestine and the muscle layer of the bowel wall and then spread to the lymph nodes and elsewhere in the body. Treatment at these later stages is less successful, so early detection and treatment is crucial.

Symptoms are often absent or ignored. The first symptoms of bowel cancer include:

• Blood in the stool. This can cause black, tarry feces or a small amount only detectable through testing for fecal occult blood. 
• Change in normal bowel habits lasting more than 6 weeks; diarrhea, constipation, or more frequent bowel movements.
• Abdominal pain.
• Unexplained weight loss.

As cancer advances, it may cause bleeding leading to anemia. Anemia causes breathlessness and fatigue.

A bowel cancer tumor can an obstruction in the bowel, or in rectal cancer, in the rectum. Symptoms of obstruction are:

• Constipation, or the sensation that feces cannot be completely passed. 
• Bloating, especially around the navel.
• Abdominal pain.
• Vomiting.

The symptoms of bowel cancer are the same as other conditions of the digestive system. If you experience any symptom listed above, see your health care provider for further testing. 

Risk factors include:

• Age: Most cases develop in patients 50 and over.
• History of developing polyps in colon or rectum.
• Family history of bowel cancer.
• History of ulcerative colitis, inflammatory bowel disease or Crohn’s disease.
• History of cancer, especially prior colorectal cancer and in women: ovary, uterus or breast cancer.
• Certain hereditary disorders or syndromes such as familial adenomatous polyposis. 
• Lifestyle risks: Smoking, obesity, alcohol abuse, lack of exercise, a diet insufficient in vegetables and fruit, or containing excessive red meat.

Different types of colorectal tests may be recommended. These include:

• Digital rectal examination
• Fecal occult blood test (FOBT)
• Endoscopy, including sigmoidoscopy and colonoscopy. During colonoscopy, polyps can be removed and biopsy samples taken.

In the US, endoscopy and FOBT are favored. X-ray examination via barium enema has fallen out of preference. A barium meal is still frequently used to exam the upper digestive tract.

Surgery is the primary treatment for bowel cancer. Procedures range from removal of polyps during endoscopic examination, to removing all or part of the colon, restructuring the intestines to pass feces through a stoma; a permanent opening in the abdominal wall. Radiotherapy is not used for cancer in the colon, as it is difficult to focus the radiation because of natural movement of the bowels. Radiation can be used to treat rectal cancer, as the rectum is less mobile.