Skip to content

    Colorectal Cancer Health Center

    Font Size

    Rectal Cancer Treatment (PDQ®): Treatment - Patient Information [NCI] - General Information About Rectal Cancer

    Rectal cancer is a disease in which malignant (cancer) cells form in the tissues of the rectum.

    The rectum is part of the body's digestive system. The digestive system removes and processes nutrients (vitamins, minerals, carbohydrates, fats, proteins, and water) from foods and helps pass waste material out of the body. The digestive system is made up of the esophagus, stomach, and the small and large intestines. The first 6 feet of the large intestine are called the large bowel or colon. The last 6 inches are the rectum and the anal canal. The anal canal ends at the anus (the opening of the large intestine to the outside of the body).
    Anatomy of the lower digestive system, showing the colon and other organs.

    See the following PDQ summaries for more information about rectal cancer:

    Age and family history can affect the risk of rectal cancer.

    Anything that increases your chance of getting a disease is called a risk factor. Having a risk factor does not mean that you will get cancer; not having risk factors doesn't mean that you will not get cancer. Talk with your doctor if you think you may be at risk. The following are possible risk factors for rectal cancer:

    • Being aged 40 or older.
    • Having certain hereditary conditions, such as familial adenomatous polyposis (FAP) and hereditary nonpolyposis colon cancer (HNPCC or Lynch syndrome).
    • Having a personal history of any of the following:
      • Colorectal cancer.
      • Polyps (small pieces of bulging tissue) in the colon or rectum.
      • Cancer of the ovary, endometrium, or breast.
    • Having a parent, brother, sister, or child with a history of colorectal cancer or polyps.

    Signs of rectal cancer include a change in bowel habits or blood in the stool.

    These and other signs and symptoms may be caused by rectal cancer or by other conditions. Check with your doctor if you have any of the following:

    • A change in bowel habits.
      • Diarrhea.
      • Constipation.
      • Feeling that the bowel does not empty completely.
      • Stools that are narrower or have a different shape than usual.
    • Blood (either bright red or very dark) in the stool.
    • General abdominal discomfort (frequent gas pains, bloating, fullness, or cramps).
    • Change in appetite.
    • Weight loss for no known reason.
    • Feeling very tired.
    1 | 2 | 3
    1 | 2 | 3
    Next Article:

    Today on WebMD

    Colorectal cancer cells
    The right diagnosis is the most important factor.
    man with a doctor
    Our health check will steer you in the right direction.
    sauteed cherry tomatoes
    Fight cancer one plate at a time.
    bladder cancer x-ray
    Do you know the warning signs?
    Colon vs Rectal Cancer
    New Colorectal Treatments
    can lack of sleep affect your immune system
    Cancer Facts Quiz
    Virtual Colonoscopy
    Picture of the Colon
    Vitamin D