Colorectal cancer is cancer that grows in the colon or rectum. Colorectal cancer can start anywhere in the large intestine. Most colorectal cancers start as polyps— abnormal growths—inside the colon or rectum. Over a long period of time, polyps may become cancerous.
What causes colorectal cancer, and who is at risk of developing it?
The exact cause of most colorectal cancers is not well known. About 75% of colorectal cancers occur in people who do not have any risk factors. However, some things may increase a person’s risk of developing colorectal cancer. Those who are at increased or high risk should talk to their healthcare provider about when to start screening.
Some factors include:
What are the symptoms of colorectal cancer?
People who have polyps or colorectal cancer don’t always have symptoms. This is especially true in the early stages of cancer. If there are symptoms, they may include:
If you have any of these symptoms, talk to your doctor. These symptoms may be caused by something other than cancer, but the only way to know is to see your doctor.
Is there anything I can do to reduce my risk for colorectal cancer?
The best way to lower your risk of colorectal cancer is by having regular screening tests beginning at age 50. Scientific studies have shown that screening reduces deaths from colorectal cancer. Screening tests can find and remove polyps (abnormal growths) in the colon and rectum before they turn into cancer. If everyone aged 50 or older had regular screening tests, up to 60% of deaths from colorectal cancer could be prevented.
Studies also show that people who are at a healthy weight and are physically active often have a lower risk of colorectal cancer. The role of diet in preventing colorectal cancer is not well known. In general, medical experts recommend a diet low in animal fats and high in fruits, vegetables and whole grains. This diet also may reduce the risk of colorectal cancer. In addition, researchers are trying to understand how the use of certain vitamins and supplements such as NSAIDs, Vitamin D, calcium, and folic acid may affect the risk for colorectal cancer.
What is cancer screening?
Screening is when a test is used to look for a disease before there are any symptoms. Cancer screening tests, including those for colorectal cancer, are effective when they can detect disease early. Detecting disease early can lead to more effective treatment. (These are different from diagnostic tests, which are used when a person has symptoms and are intended to find out what is causing the symptoms.)
Why should I get screened for colorectal cancer?
Screening for colorectal cancer saves lives. Colorectal cancers almost always develop from precancerous polyps (abnormal growths) in the colon or rectum. Screening tests can find polyps, so they can be removed before they turn into cancer. Screening tests also can find colorectal cancer early, when treatment works best and the chance for a full recovery is very high. Having regular screening tests beginning at age 50 could save your life.