Colon cancer is malignant cells found in the colon or rectum. The colon and rectum are parts of the large intestine which are part of the digestive system. Because colon cancer and rectal cancers have many features in common, they are sometimes referred to together as colon cancer. Cancerous tumors found in the colon or rectum may also spread to other parts of the body.
Excluding skin cancers, colon cancer is the third most common cancer in both men and women. The American Cancer Society estimates that about 140,000 colon cancer cases and about 50,000 deaths from colon cancer occur each year. The number of deaths due to colon cancer has decreased, which is attributed to increased screening and polyp removal and to improvements in cancer treatment.
A type of cancer called adenocarcinoma accounts for more than 95 percent of cancers in the colon and rectum and is usually what is meant by the term colorectal cancer. There are other types of cancer that can be found in the colon and rectum, but they are rare.
Types of cancer in the colon and rectum include:
The following are the most common colon cancer symptoms, however, each individual may experience symptoms differently. People who have any of the following symptoms should check with their physician, especially if they are over 50 years old or have a personal or family history of the disease:
The symptoms of colon cancer may resemble other conditions, such as infections, hemorrhoids, and inflammatory bowel disease. It is also possible to have colon cancer and not have any symptoms. Always consult your physician for a diagnosis.
Risk factors may include:
The exact cause of most colon cancer is unknown, but the known risk factors listed above are the most likely causes. A small percentage of colon cancers are caused by inherited gene mutations. People with a family history of colorectal cancer may wish to consider genetic testing. The American Cancer Society suggests that anyone undergoing such tests have access to a physician or geneticist qualified to explain the significance of these test results.
Prevention of colon cancer
Although the exact cause of colon cancer is not known, it may be possible to lower your risk of colon cancer with the following:
The following screening guidelines can lower the number of cases of the disease and can also lower the death rate from colorectal cancer by detecting the disease at an earlier, more treatable stage.
Colon cancer screening guidelines from the American Cancer Society for early detection include:
If a person has symptoms that might be caused by colon cancer, you physician will want to get a complete medical history and do a physical exam; he or she may also do certain tests to look for cancer. Many of these tests are the same as those done to screen for colon cancer in people without symptoms.
When colon cancer is diagnosed, tests will be performed to determine how much cancer is present and if the cancer has spread from the colon or rectum to other parts of the body. This is called staging; it is an important step toward planning a treatment program. The stages of colon cancer are:
Stage 0: The cancer is found in the innermost lining of the colon or rectum.
Stage I: cancer has spread beyond the innermost lining of the colon or rectum to the second and third layers.and has not spread to the outer wall or outside of the colon or rectum.
Stage II: cancer has spread through into the wall or outside the colon or rectum to nearby tissue, however, the lymph nodes are not involved.
Stage III: cancer has spread to nearby lymph nodes but has not spread to other organs in the body.
Stage IV: cancer has spread to other parts of the body such as the lungs.
Specific treatment for colon cancer will be determined by your physician based on:
After the colon cancer is diagnosed and staged, your physician will recommend a treatment plan which may include: