Colon Cancer: Common and Curable
Though it's the second leading cause of cancer deaths in the United States, colon cancer is also one of the most curable cancers.
Where is the colon? It's part of the large intestine—the final portion of the digestive tract. Measuring about six feet in length, the colon comprises a significant part of the large intestine. In most patients, colon cancer begins as tiny polyps (growths) on the lining of the colon, which over a long period of time, become cancerous. Although colon polyps in most people do not ultimately develop into cancer, their presence does warrant regular monitoring and, in many cases, removal. While many factors can cause colon polyps to become cancerous, the following specific factors can predispose you to developing colon cancer:
- Family history of colon or rectal cancer
- Family history of colon polyps
- Diet high in fat and low in fruits and vegetables
- Excessive alcohol consumption
- Lack of physical activity
- Diet high in red meat
- Diagnosis of inflammatory bowel disease (Crohn's disease or ulcerative colitis)
Symptoms Are Slow to Evolve
"Colon cancer often causes no symptoms until it has advanced to a more serious stage, at which point, treatment becomes more difficult and, unfortunately, possibly unsuccessful," explains Dr. Stanley Rosenberg, a gastroenterologist at Boston's Beth Israel Deaconess Medical Center. Accordingly, he adds that early detection is extremely important to the prevention and successful treatment of colon cancer.
The following symptoms may indicate the presence of colon cancer:
- Chronic abdominal pain
- Increased transient abdominal cramping
- Yellowing or jaundice of your skin, eyes, or the underside of your tongue (due to spread to the liver)
- Rectal bleeding
- Change in bowel habits (narrowing of the stool, increased flatulence, increased mucous, stool that is particular malodorous, or floats to the top of the toilet water)
- Blood in the stool
- General weakness, or other symptoms of anemia (blood iron deficiency)
Early Detection: It Can Save Your Life
The presence of any of the symptoms noted above should send you running to your healthcare provider. Since symptoms often don't arise until after the disease has progressed to a more advanced stage, you should be having regular colon cancer screenings once you reach age 50—when the risk of colon cancer begins to increase markedly. Doctors estimate that up to 50% of all colon cancers could be prevented by regular screening.
Methods of screening include:
- Digital Rectal Examination—(yearly) as part of your annual physical exam.
- Fecal Occult Blood Test—(yearly) a laboratory test for tiny amounts of blood in your stool. While still not widely utilized, fecal occult tests that you can do at home are now available.
- Flexible Sigmoidoscopy—(every five years) an examination of the rectum and lower colon via the insertion of a thin tube with a light at the end of it.
- Colonoscopy—strongly suggested every five years for patients with risk factors for colon cancer (especially a family history of colon or rectal cancer), and every 10 years for everyone else age 50 or older. This test, which uses a longer tube than the flexible sigmoidoscopy, allows for a more thorough examination of the entire colon, including removal and biopsy of a polyp found during the examination.
- Virtual Colonoscopy—a relatively new test that uses a CT scan to create a three dimensional image of the bowel that can be examined by a radiologist and a gastroenterologist. This method causes less discomfort than a regular colonoscopy because doctors do not have to insert a long tube or fill the colon with liquid barium, but it doesn't allow for the removal and biopsy of polyps. Ask your doctor if this procedure is appropriate for you.
Treatment Depends on When You Start
If you have a colon exam that indicates the presence of polyps, a biopsy (removal of the polyp for examination) is done. If a polyp is found to be cancerous, surgery to remove the polyp(s) is usually performed and further treatment will depend mainly on what stage the cancer has progressed to. The stages of cancer refer to which tissue has been affected by the cancer.
The cancer is contained to the inner lining of the colon or the inside wall of the colon. Surgery is usually limited to removing the tissues found to be cancerous.
The cancer has spread to the deeper layers of the colon or outside the colon to nearby tissue, but not to the lymph nodes. Surgery is performed to remove the cancerous part of the colon and a small amount of healthy tissue surrounding the cancerous cells. In addition, nearby lymph nodes are removed and tested to determine if the cancer has spread. Chemotherapy or radiation therapy may be recommended to kill any remaining cancer cells that may not have been removed by surgery.
Third and Fourth Stages:
The cancer has spread beyond the colon and tissue near the colon to the lymph nodes and/or other parts of the body. Surgery is performed to remove cancerous parts of the colon and surrounding tissues. In addition, surgery to remove all or part of other organs to which the cancer has spread may be done. Radiation therapy and chemotherapy may also be utilized. Biological therapy—the use of drugs that cause the body itself to fight cancer cells—is available on an experimental basis only.
Prevention: What Can You Do?
The importance of regular screening tests for preventing colon cancer can not be emphasized enough. In addition, the following steps can help limit your risk for colon cancer:
- Eat a diet high in fruits and vegetables and low in animal fat. Though a diet high in fiber has long been thought to protect against colon cancer, some recent studies have indicated otherwise.
- Limit your consumption of alcohol.
- Limit your consumption of meat, especially red meat. When eating red meat, choose cuts low in fat, slow cook the meat, and avoid eating meat, fish, and poultry that has been burned, charred, or heavily browned, as these cooking methods may contribute to the development of colon cancer.
- Exercise regularly and try to maintain a healthy weight.
- Don't smoke.
New Research May Aid Prevention
In recent years, studies have uncovered a number of previously unknown factors related to colon cancer.
One study has led to the belief among most medical professionals that a large portion—up to an estimated 20%—of all colon cancer cases may be related to hereditary factors. Two such factors have been specifically identified: familial adenomatous polyposis and hereditary non-polyposis colon cancer (Lynch Syndrome). People with these two diseases are more likely than others to develop colon cancer. Another form of inherited colon cancer that effects only Jewish people of Eastern European descent has recently been discovered, although little else about it is known.
In addition to helping prevent heart attack and stroke , aspirin taken once daily may help to prevent the development of colon polyps and, thus, colon cancer. However, aspirin can cause stomach bleeding and other side effects if taken over long periods of time. Studies are still determining if taking aspirin is a safe way to prevent colon cancer.
Non-Steroidal Anti-Inflammatory Drugs
Ibuprofen has also been shown to decrease polyp formation, the main precursor of colon cancer. However, this drug has many side effects and is difficult to take on a chronic basis.
Vitamins and Minerals
One study has shown that regular intake of folic acid may greatly reduce the risk of developing colon cancer. Another study has shown that taking daily calcium supplements also may reduce your risk of developing colon cancer.
Finally, a recent study has shown that women who are insulin resistant—a condition that is often a precursor to diabetes—are at a much greater risk of developing colon cancer than women who are not insulin resistant.
Researchers are learning more and more about colon cancer, but since screenings can catch potential problems early on, why not just do it?
American Cancer Society
National Cancer Institute
Canadian Cancer Society
Colon Cancer Canada
Cancer Information Service. National Cancer Institute website. Available at: http://cis.nci.nih.gov/.
Colon cancer. CancerNet. National Cancer Institute website. Available at: http://www.cancer.gov/cancerinfo/pdq/treatment/colon.
Last reviewed July 2008 by Igor Puzanov, MD
Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.
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