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About Rectal Cancer

Rectal cancer is a disease in which cancerous cells form in the tissues at the end of the large intestine, or rectum.

Signs & Symptoms

These are signs of rectal cancer:

  • Blood (bright red or dark) in the stool
  • A change in bowel habits
    • Diarrhea
    • Constipation
    • A feeling that the bowel does not empty
    • Stools that are narrower or have a different shape than usual
  • General pain or discomfort in the abdomen
  • Change in appetite
  • Sudden, unexplained weight loss
  • Feeling unusually 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 rectal cancer from the National Cancer Institute.

Image of the Rectum

Anatomy of the lower digestive system, showing the colon and other organs.
Anatomy of the lower digestive system, showing the colon and other organs.

Specialties & Treatments

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 for rectal cancer:

  • Surgery
  • Radiation therapy
  • Chemotherapy
  • Targeted therapy
  • Radiofrequency ablation

Huntsman Cancer Institute’s Gastrointestinal (GI) Cancers Program provides comprehensive, compassionate, state-of-the-art care for cancers of the digestive system. Our experts treat and diagnose all types of GI cancers and conditions.

Learn more about types of cancer treatments.

Find a Rectal Cancer Doctor

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 rectal cancer increases with age. These are other risk factors for rectal cancer:

  • A personal history of colon, rectal, or ovarian cancer or high-risk colorectal polyps
  • A family history of colon or rectal 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
  • Smoking
  • Being obese
  • Being black

Learn more about ways to prevent cancer and about family history and genetic counseling.

Diagnosis & Stages

Diagnosis of Rectal 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.

Doctors use these tests to screen for and diagnose rectal cancer:

  • Colonoscopy: Using a lighted scope, the health care provider looks at the full length of the colon to look for anything unusual. If polyps are found, the provider removes them to test for cancer or to prevent them from turning in to 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 and rectum for anything unusual. If polyps are found, the provider removes 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 or rectum.
  • Fecal occult blood test (FOBT): This checks for small amounts of blood in the stool. The stool sample is usually collected at home and delivered to the lab for testing. Blood in the stool may be a sign of cancer in the colon or rectum.
  • 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 and rectum are 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 Rectal Cancer

Cancer stages show whether cancer has spread within or around the rectum 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 rectum wall. These abnormal cells may become cancer and spread.
  • Stage 1: The cancer has formed and grown into the wall of the rectum.
  • Stage 2 (2A, 2B, 2C): The cancer has grown through the rectal wall, but has not invaded other organs.
  • Stage 3 (3A, 3B, 3C): The cancer has grown into the rectal wall and has spread to the lymph nodes nearby.
  • Stage 4 (4A, 4B): The cancer has spread to organs away from the rectum 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 rectal cancer spreads to the bone, the cancer cells in the bone are actually rectal cancer cells. The disease is metastatic rectal cancer, not bone cancer.

Learn more about the stages of rectal cancer from the National Cancer Institute.

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