The large intestine (also called the large bowel), consists of the colon and rectum, which is the final part of your digestive system. Cancer of the lining of the large intestine is called colorectal cancer.
Although colorectal cancer is the second most common cause of death from cancer in the United States, it is one of the few cancers that doctors can prevent.
Most colorectal cancers start out as small growths (polyps) which form on the lining of the large intestine. Over a period of five to ten years, some of these polyps can become cancers. Most people with colorectal polyps are unaware of their presence until the polyps are found during a colorectal cancer screening. Because most polyps - and many colon cancers - have no symptoms, it's very important to have a colorectal cancer screening.
In some cases, colorectal cancer may cause:
- A change in bowel habits, such as diarrhea or constipation
- Blood in bowel movements
- Abdominal pain
- Weight loss
Note: many of these symptoms can be caused by other health problems, and often are not due to colorectal cancer.
Polyps are small growths on the lining of the colon that are caused by uncontrolled growth of abnormal cells. Most colorectal cancer starts as polyps, some of which - over five to ten years - can turn into colon cancer. If you are over 50, you are at risk for developing polyps. If someone in your family has had intestinal cancer, you have a greater than average chance of developing colorectal polyps or cancer.
Things that may increase your chances of developing colorectal cancer:
- A personal history of colorectal cancer or polyps
- A family history of colorectal cancer or polyps
- An inflammatory bowel disease, such as ulcerative colitis, or Crohn's disease
The best test to find colorectal polyps is a colonoscopy, which checks your entire large intestine for cancer and polyps. It is a very effective test that prevents cancer in as much as 90 percent of patients, because any polyps are painlessly removed during the exam. Finding and removing these polyps dramatically reduces the chances of cancer developing. You will be sedated during the procedure, and will need to have someone drive you home. Plan to be at the hospital for about three hours. More information about colorectal cancer screening.
If colorectal cancer is found at an early stage, a person's chances of living longer than five years may be as great as 95%. If colorectal cancer is found at a late stage, a person may have only a 10% chance of living for five years. The earlier cancer is found, the better your chances of survival.
For larger cancerous growths, a surgeon will make an incision in the abdomen to remove the tumor and part of the colon or rectum. Occasionally, the surgeon will create an opening in the abdomen, to divert bowel movements into a colostomy bag. In some cases, the surgeon will rejoin the colon and repair the opening in the abdomen in a later operation. The colostomy may be permanent for patients who have had a tumor in the lower rectum.
Radiation and chemotherapy are sometimes used in addition to surgery.