About Colon Cancer
Colon cancer is a disease where cancerous cells form in the tissues of the large intestine, or colon.
Signs & Symptoms
These are signs and symptoms of colon cancer:
- A change in bowel habits
- Blood in the stool
- Diarrhea, constipation, or feeling that the bowel does not empty all the way
- Stools that are narrower than usual
- Frequent gas pains, bloating, fullness, or cramps
- Weight loss for no known reason
- Feeling very tired
Many other health problems can also cause these signs. If you have any of these signs, see your doctor as soon as possible.
Learn more about colon cancer from the National Cancer Institute.
Image of the Colon
Specialties & Treatments
Huntsman Cancer Institute offers different types of treatment for people with colon cancer. The treatment or combination of treatments each patient has depends on the stage of the cancer, recommendations of the care team, and the patient’s wishes. These are the most common types of treatment:
- Radiation therapy
- Targeted therapy
- Radiofrequency ablation
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Causes & Risk Factors
Anything that increases your chance of getting a disease is called a risk factor. Having a risk factor does not mean you are sure to get cancer. It means your chances are higher than the average person’s. Talk with your doctor to learn more about your cancer risk.
The chance of getting colon cancer increases with age. These are other risk factors of colon cancer:
- A personal history of colon, rectum, or ovarian cancer or high-risk colorectal polyps
- A family history of colon cancer in a parent, child, or sibling
- Changes in certain genes that increase the risk of familial adenomatous polyposis (FAP) or hereditary nonpolyposis colorectal cancer (Lynch syndrome)
- A personal history of Crohn’s disease or chronic ulcerative colitis
- Having three or more alcoholic drinks per day
- Being obese
- Being black
Diagnosis & Stages
Diagnosis of Colon Cancer
Screening looks for cancer before you have symptoms. Screening can also check for anything unusual if you notice changes in your bowel habits or have blood in your stool. Screening can rule out an issue or help find cancer at an early stage, when it may be easier to treat.
These tests screen for and diagnose colon cancer:
- Colonoscopy: Using a lighted scope, the health care provider looks at the full length of the colon for anything unusual. If polyps are found, the provider will remove them to test for cancer or to prevent them from turning into cancer in the future.
- Screening colonoscopies are recommended for everyone starting at age 45.
- Sigmoidoscopy: Using a lighted scope, the health care provider looks at the lower part of the colon for anything unusual. If polyps are found, the provider will remove them to test for cancer or to prevent them from turning into cancer in the future.
- Barium enema: After filling the lower colon with a liquid that contains barium, which improves the image quality, health care providers take x-rays to look for polyps or anything unusual in the colon.
- Fecal occult blood test (FOBT): This test looks for small amounts of blood in the stool. The stool sample is usually collected at home and delivered to the laboratory for testing. Blood in the stool may be a sign of cancer in the colon.
- Physical exam and history: A health care provider examines your body for signs of disease. Your personal health habits, past illnesses, and symptoms help guide the exam.
- Digital rectal examination (DRE): As part of the physical exam, the health care provider may examine the anus and rectum with a gloved finger.
- Virtual colonoscopy: The colon is examined through a computed tomography scan that creates images of the colon.
- Biopsy: The health care provider removes cell or tissue samples so they can be viewed under a microscope to check for signs of cancer. Biopsies are often done as part of a colonoscopy.
Stages of Colon Cancer
Staging is the process that shows whether cancer has spread within the colon or to other parts of the body. Cancer spreads in the body in three ways: through tissue, the lymph system, or the blood.
These are the stages used for colon cancer:
- Stage 0: Stage 0 cancers are often called carcinoma in situ. For stage 0 colon cancer, tests have found abnormal cells on the inside of the colon wall.
- Stage I: Cancer has formed and grown into the wall of the colon.
- Stage II (IIA, IIB, IIC): Cancer has grown through the colon wall, but has not invaded
- Stage III (IIIA, IIIB, IIIC): The cancer has grown into the colon wall and has spread to the lymph nodes nearby.
- Stage IV (IVA, IVB): The cancer has spread to organs away from the colon such as the
liver or lungs.
When cancer spreads from where it started to another part of the body, it is called metastasis. These metastatic cancer cells are the same type of cancer as the primary tumor. For example, if colon cancer spreads to the bone, the cancer cells in the bone are actually colon cancer cells. The disease is metastatic colon cancer, not bone cancer.
Learn more about the stages of colon cancer from the National Cancer Institute.