Colon cancer forms in the lining of the colon. Rectal cancer forms in the lining of the rectum, the last several inches of the large intestine terminating in the anus. Either of these cancers is called colorectal cancer.
In the United States, colon cancer is the second deadliest form of cancer when considering both men and women together. Each year about 150,000 people will be diagnosed with colon cancer, and 50,000 people will die from the disease, according to the American Cancer Society.
Though scientists are unsure of exactly what causes colon and colorectal cancer, some risk factors have been identified.
- Being over age 50
- Polyps, growths inside the colon and rectum that may become cancerous
- A high-fat diet
- Family or personal history of colon cancer or polyps
- Ulcerative colitis, Crohn's Disease or other inflammatory bowel diseases involving the colon
- Sedentary lifestyle
- Radiation therapy for cancer
Many cases of colon or colorectal cancer have no symptoms or warning signs until the cancer has advanced. However there are some symptoms that may indicate colon cancer, but these symptoms can sometimes be confused for other conditions such as hemorrhoids. You should consult with your doctor if you experience any of these symptoms and are unsure of the cause.
Warning Signs and Symptoms
- Abdominal pain or tenderness in the lower abdomen
- Bloody stool
- Diarrhea, constipation or other changes in bowel functions
- Narrower than normal stools
- Unexplained anemia
- Unexplained weight loss
- Bloating, fullness or cramps
A colon polyp is a growth of extra tissue in the lining of the rectum or colon. While some can be cancerous, most are not. However, almost all colon cancer does begin as a polyp. Therefore, by removing polyps early, the chances of it growing into colon cancer are eliminated. People with a higher risk for developing polyps are anyone over age 50, those who have had polyps previously or those who have a family history of polyps or colon cancer. However you can still be at risk for polyps or colon cancer without having a family history of either condition. In fact, 80 percent of those who are diagnosed with colon cancer have no family history.
Polyps generally do not cause symptoms. If a patient does have symptoms, they can include blood in their underwear or on toilet paper after a bowel movement, blood in stool, or constipation or diarrhea that has lasted more than a week.
Polyps can be removed during a colonoscopy. If precancerous colon polyps are removed, the chance of the polyp turning into cancer is eliminated. Colon cancer is also highly treatable when discovered early. Depending on an individual's medical and family history, colonoscopies are typically recommended every one, three, five or 10 years.
Treatments and Procedures
The three primary treatment options available for colon cancer are surgery, chemotherapy and radiation. Treatment options for colon cancer depend on the stage of the cancer, whether the cancer has recurred and the patient's general health. The surgical option, a partial colectomy, is the main treatment and includes removing the affected portion of the colon. How much of the colon is removed and whether it is done in conjunction with other treatments will depend on the location of the cancer, how deep it has penetrated the wall of the bowel and if it has spread to the lymph nodes or other parts of the body.
In surgical treatment, the part of the colon that contains the cancer, as well as portions of healthy colon on either side, will be removed to ensure no cancer is left behind. Nearby lymph nodes will be removed and tested at the same time. Usually the doctor is able to reconnect the healthy portions of the colon, but if that is not possible the patient will have a temporary or permanent colostomy bag. A colostomy bag is a device that is worn on the skin discreetly under the clothing and is attached to the remaining bowel. Waste material travels into this bag which is then disposed of, and the bag is replaced as needed. Sometimes, a colostomy is done temporarily to give the bowel time to heal. It may become permanent if too much of the colon or the rectum has to be removed.
If the cancer is small, early stage and localized in a polyp, it is possible it may all be removed during a colonoscopy.
If the cancer is very advanced or the patient's health is extremely poor, surgery may be done simply to provide comfort. This is an operation that will relieve a blockage of the colon to improve symptoms. This will not cure cancer but may relieve pain and bleeding.
Chemotherapy can be used after surgery to destroy any remaining cancer cells, and may be recommended by the doctor if the cancer has spread beyond the lining of the colon. Chemotherapy can be used in conjunction with radiation. Radiation therapy uses powerful energy sources to kill any cancer cells that may remain after surgery or to shrink large tumors before an operation. This option is rarely used in the early stages of colon cancer.
Preventing Colon Cancer
Getting screened is the first step in preventing colon cancer. Several screening options are available, including colonoscopy and flexible sigmoidoscopy. Regular colonoscopies should begin at age 50 for people with an average risk for developing colon cancer. If you have a family history of polyps or colon cancer, many physicians may recommend getting your first colonoscopy at age 40 or even earlier depending on your history. Some recent studies indicate that African-Americans may need to start screening at age 45. More frequent and earlier screening is recommended if you are at high risk for colon cancer.
Lifestyle changes can also be made to reduce the risk of colon cancer:
- Add fruits, whole grains and vegetables to your diet
- Limit saturated fat
- Limit alcohol
- Eat a varied diet
- Quit smoking
- Stay active and maintain a healthy body weight