The colon makes up the last six feet of the large intestines and absorbs water, electrolytes and nutrients from food and transports them into the bloodstream.
Colon cancer is fairly common, affecting about 7 percent of the American population. Although it is a life-threatening disease, it is a highly curable form of cancer if found early. Regular check-ups and screenings are very important.
Although the exact cause of colon cancer is unknown, certain risk factors have been identified that may increase your chance of developing the disease. These include:
- Age — The majority of colon cancers are diagnosed in people aged 50 or older, although the disease affects all ages.
- Bowel disease — A history of colorectal cancer, intestinal polyps and diseases such as chronic ulcerative colitis and Crohn's disease increase your chance of developing colon cancer.
- Diet and exercise — A diet high in fat, particularly from animal sources, and an inactive, sedentary lifestyle can increase your chance of developing colon cancer.
- Ethnic background and race — Jews of Eastern European descent, called Ashkenazi Jews, have a higher rate of colon cancer. African-Americans and Hispanics have a higher death rate from colon cancer, which may be caused by insufficient screenings, poor diet and lack of exercise.
- Family history/genetic factors — Specific genes have been identified that increase your chance of having colon cancer. If you have a strong family history of colorectal cancer, as defined by cancer or polyps in a first-degree relative younger than 60 or two first-degree relatives of any age, you're at increased risk for developing colon cancer.
- Smoking and alcohol — Research suggests that smokers and heavy drinkers have an increased risk of developing colon cancer.
Common signs and symptoms of colon cancer include:
- A change in bowel habits
- Diarrhea, constipation or feeling that the bowel does not empty completely
- Blood, either bright red or very dark in the stool
- Stools that are narrower than usual
- General abdominal discomfort such as frequent gas pains, bloating, fullness or cramps
- Weight loss with no known reason
- Constant tiredness
Your doctor will begin the evaluation by recording your medical history, asking about symptoms you may be experiencing and conducting a thorough physical examination. He or she may recommend one or more of the following diagnostic tests:
- Barium Enema — Also known as a lower gastrointestinal series, this test involves taking X-rays of the large intestines.
- Biopsy — In this test, a small amount of tissue from the suspected area is removed for examination by a pathologist to make a diagnosis.
- Colonoscopy — Colonoscopy is performed to see inside the rectum and the entire colon and remove polyps or other abnormal tissue for examination under a microscope. In addition to the standard colonoscopy, UCSF Medical Center offers a virtual colonoscopy.
Treatment for colon cancer may include surgery, radiation therapy or chemotherapy, or a combination of these approaches.
Surgery is the most common treatment for all stages of colon cancer. Depending on the stage and size of your tumor, your doctor will remove your cancer with one of the following methods:
- Local excision — This surgical approach is used for very early stage cancers. It involves inserting a tube through the rectum into the colon and removing the cancer, rather than making a cut in the abdominal wall. If the cancer is found in a polyp, the procedure is called a polypectomy.
UCSF Research & Clinical Trials
Reviewed by health care specialists at UCSF Medical Center.