Colorectal cancer 101
Colorectal cancer is a disease that starts in the colon or the rectum—parts of your body's digestive system. It is one of the most common cancers, according to the National Cancer Institute (NCI).
Colorectal cancer occurs most often in men and women who are older than 50, but new cases of this cancer are occurring at an increasing rate among younger adults. Those with a family history of colorectal cancer, or who have certain inherited genes, also have an increased risk for the disease. So do those who have had colorectal polyps or inflammatory bowel disease. Other risk factors include being overweight, smoking and drinking an excessive amount of alcohol. Diets high in red or processed meat also may play a role.
The symptoms of colorectal cancer may vary from person to person. It's also possible to have colorectal cancer and no symptoms at all. But if you have any of the following conditions, the NCI says you should check with your doctor:
- A change in bowel habits, such as diarrhea, constipation or narrowing of the stool.
- A feeling that your bowel doesn't empty completely.
- Rectal bleeding or blood in the stool.
- Frequent cramping pain in your lower belly.
- Weight loss with no known reason.
- Weakness and fatigue.
To determine what is causing your symptoms and if you have colorectal cancer, your doctor may look at your medical history, perform a physical exam and order one or more tests. Those tests could include:
- A blood test to look for anemia or to check your liver function.
- A diagnostic colonoscopy—an examination of the rectum and entire colon using a lighted instrument called a colonoscope.
- A biopsy—a small piece of tissue is removed using a special instrument passed through the colonoscope.
- Imaging tests to look at suspicious areas that might be cancer.
Yes. But it's important to find the disease early. The earlier colorectal cancer is detected, the easier it is to treat and the better your chances for a full recovery. For early stages of colorectal cancer, surgery may be all that is required. More advanced stages may require other treatments such as chemotherapy or radiation therapy.
The American Cancer Society (ACS) recommends that people who are at average risk for colorectal cancer begin regular screening for the disease at age 45. The ACS says people should use one of the following screening options:
- A fecal occult blood test (FOBT) or a fecal immunochemical test (FIT) every year.
- A stool DNA test every three years.
- A flexible sigmoidoscopy every five years.
- A colonoscopy every 10 years.
- A virtual colonoscopy every five years.
Your doctor can help you choose the screening plan that's right for you.
To learn more about colon cancer, visit the Colorectal Cancer health topic center. You can also find out more at these websites: