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Rectal Cancer by Laurie LaRusso, MS, ELS and Pamela Jones, MA

Definition

Rectal cancer is cancer in the rectum, the last part of the large intestine. It allows waste to pass to the anus and out of the body.

Cancer occurs when cells in the body divide without control or order. If cells keep dividing, a mass of tissue (a growth or tumor) forms. The term cancer refers to malignant tumors. They can invade nearby tissue and spread to other parts of the body.

Causes

The cause is unknown.

Risk Factors

Research shows that certain risk factors are associated with the disease, including:

Age: 50 or older
Hereditary conditions (eg, familial polyposis or lynch syndrome)
History of colon or rectal cancer or polyps
Family history of colorectal cancer, especially a parent, sibling, or child
Radiation therapy for prostate cancer
Obesity
Diet high in fat and low in fiber
Smoking
Heavy alcohol intake
Physical inactivity

Symptoms

Rectal cancer often does not have any symptoms. Some symptoms associated with it include:

Blood (bright red or very dark) in the stool
A change in bowel habits, such as diarrhea , constipation , or the bowel does not empty completely
Stools have a different shape than usual (eg, narrower)
Abdominal discomfort (gas pains, bloating, fullness, and/or cramps)
Change in eating habits
Unexplained weight loss
Frequently feeling tired or run down

These may also be caused by less serious health conditions. See a doctor if you have these symptoms.

Diagnosis

The doctor will ask about symptoms and medical history and do a physical exam.

Screenings for cancer or precancerous polyps include:

Digital rectal exam—the doctor's gloved finger will examine the rectum for lumps or growths
Fecal occult blood test —a test to check for hidden blood in the stool
Colonoscopy —examination of the rectum and colon using a lighted tube called a colonoscope
Sigmoidoscopy —examination of the lower colon using a lighted tube called a sigmoidoscope
Barium enema —rectal injection of barium coats the lining of the colon and rectum; done before x-rays to create better images of the lower intestine
CT colonography —radiology test that looks at your large intestines

Additional tests may confirm the presence of cancer, determine what stage the cancer is in, and/or determine if the cancer has spread:

Biopsy —removal of tissue to test for cancer
Polypectomy —removal of a polyp during a sigmoidoscopy or colonoscopy
Blood tests to look for anemia and cancer markers in the blood
CT scan —x-ray that uses a computer to make pictures of structures inside the body; identifies the spread of the tumor
Positron emission tomography (PET) —produces images showing the amount of functional activity in tissue; shows if the disease has spread outside the pelvis
Transrectal ultrasound—an ultrasound probe inserted into the rectum sends out sound waves to image the tumor

Treatment

Treatment will depend on the stage of the cancer, the spread into the wall of the rectum, and your overall health. Options include:

Surgery

Surgery is the main treatment. The tumor and nearby rectal tissue are removed. It may also involve nearby lymph nodes. The surgery may be done by:

Laparoscopy —This is for the removal of early stage cancer.
Open surgery—This is used to remove larger, later stage tumors, nearby healthy tissue, and potentially nearby lymph nodes. The doctor will look for additional cancer in the colon.

Sometimes, nearby healthy rectal or colon tissue will be removed. This is called colectomy . Healthy tissue is removed in case the cancer has spread. Often, the remaining healthy portions of the colon and rectum are reconnected. Sometimes, the end of the healthy colon is temporarily or permanently attached to an opening in the abdomen called a colostomy . It allows body waste to pass out of the body if the colon cannot do so.

Radiation Therapy

Radiation is used to kill cancer cells and shrink tumors. It is directed at the site of the tumor from a source outside the body. This therapy is aimed at the immediate area of the cancer. It is used alone or with chemotherapy .

Chemotherapy

This therapy uses drugs to kill cancer cells. It may be given in many forms, including pill, injection, and via a catheter. Drugs enter the bloodstream and travel through the body killing cancer cells. They can also kill healthy cells. This therapy is systemic, meaning it affects your entire body.

Combined chemotherapy and radiation therapy has been the preferred treatment.

If you are diagnosed, follow your doctor's instructions.

Prevention

Screening

The cause of most rectal cancer is not known. Many colon and rectal cancers can be prevented by finding and removing polyps that could become cancer. Beginning at age 50, both men and women at average risk for colon and rectal cancer should follow one of these five screening options:

Yearly fecal occult blood test or fecal immunochemical test
Colonoscopy every 10 years
Flexible sigmoidoscopy every five years
Double contrast barium enema (x-rays of the colon and rectum) every five years
CT colonography every five years

Discuss these cancer screening tools with your doctor to see which option is best for you.

People with any of the following risk factors should begin colon and rectal cancer screening earlier (at age 40) and/or undergo screening more often:

Strong family history of colorectal cancer or polyps
Family history of hereditary colorectal cancer syndromes
History of colorectal cancer or adenomatous polyps
History of chronic inflammatory bowel disease

If there a family member is diagnosed with rectal cancer, screening tests will begin when you are 10 years younger than your family member was at the age of diagnosis.

Lifestyle Changes

There are also lifestyle changes that may reduce your risk of rectal cancer, such as:

Not smoking
Being physically active (eg, exercising at least 30 minutes on most days of the week)
Reducing your alcohol intake
Maintaining a healthy weight
Eating a healthy diet (eg, high in fruits, vegetables, and fiber, and low in red meat)

RESOURCES:

American Cancer Society http://www.cancer.org/
CancerCare http://www.cancercare.org/

CANADIAN RESOURCES:

Canadian Cancer Society http://www.cancer.ca/
Colorectal Cancer Association of Canada http://www.colorectal-cancer.ca/

References:

Casciato DA. Manual of Clinical Oncology . 5th ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2004.
Cashen AF, Wildes TM. The Washington Manual; Hematology and Oncology Subspeciality Consult . 2nd ed. Wolter Kluwers; 2008.
Colon carcinoma. EBSCO DynaMed website. Available at: http://www.ebscohost.com/dynamed/what.php . Accessed March 18, 2008.
Colon and rectal cancer. National Cancer Institute website. Available at: http://www.cancer.gov/cancertopics/types/colon-and-rectal . Accessed July 17, 2008.
National colorectal cancer roundtable. American Cancer Society website. Available at: http://www.cancer.org/docroot/CRI/content/CRI_2_6X_National_Colorectal_Cancer_Roundtable.asp?sitearea .
US Preventative Task Force. Screening for colorectal cancer: US Preventive Services Task Force recommendation statement. Ann Intern Med . 2008;149:627-637. Epub 2008 Oct 6.
Washington University School of Medicine Department of Medicine. The Washington manual subspeciality series, hematology and oncology subspeciality consult series . St. Louis, MO: Lippincott Williams & Wilkins; 2008.
11/19/2010 DynaMed's Systematic Literature Surveillance DynaMed's Systematic Literature Surveillance : Kirkegaard H, Johnsen NF, Christensen J, Frederiksen K, Overvad K, Tjønneland A. Association of adherence to lifestyle recommendations and risk of colorectal cancer: a prospective Danish cohort study. BMJ. 2010;341:c5504.

Last reviewed February 2012 by Mohei Abouzied, MD

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