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Rectal Cancer

(Cancer of the Rectum)


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

Causes    TOP

Cancer occurs when cells in the body divide without control or order. These uncontrolled cells form a growth or tumor. These growths are malignant. This means they invade nearby tissue and can spread to other parts of the body. It is not clear what causes these problems in the cells. Both your genes and factors like smoking or diet may play a role.

Risk Factors    TOP

Being over 50 years of age increases your chance of rectal cancer. Other factors that may increase your chance of rectal cancer include:

  • Genetics
  • History of colon or rectal cancer, or polyps
  • Family history of colon or rectal cancer, especially a parent, sibling, or child
  • Ethnicity—African-Americans carry the highest risk of developing and dying from colorectal cancer
  • Radiation therapy for prostate cancer
  • Obesity
  • Smoking
  • Diet high in fat and low in fiber
  • Alcohol use disorder
  • Physical inactivity

Symptoms    TOP

Rectal cancer may not cause symptoms in most people. Some may have:

  • A change in bowel habits
  • Blood, either bright red, or black and tarry, in the stool
  • Stools that are narrower than usual
  • Diarrhea, constipation, or feeling that the bowel does not empty completely
  • General abdominal discomfort, such as frequent gas pains, bloating, fullness, and/or cramps
  • Unexplained weight loss
  • Constant feeling of fatigue or tiredness

Diagnosis    TOP

You will be asked about your symptoms and medical history. A physical exam will be done. Your rectum will be checked for lumps or abnormal areas.

If the doctor finds a problem during the exam, further tests may be needed. These may include:

  • Colonoscopy—a scope is passed into the colon to look for abnormal tissue
  • Sigmoidoscopy—a scope is passed into the rectum to look for abnormal tissue

A sample of abnormal tissue may be removed for a biopsy. The tissue will be closely looked at in a lab. The doctor will decide if it is cancer after these tests are complete.

  • Fecal occult blood test

Further tests may be done to find the stage of the cancer. Staging is based on factors like how far the cancer has spread. It will help to determine the treatment plan. Testing may include:

Treatment    TOP

Talk with your doctor about the best treatment plan for you. Treatment may include one or more of the following options:


Surgery is the main treatment for rectal cancer. There are several options for surgery depending on the location of the cancer and how much it has spread:

  • Polypectomy and local excision —Early stage removal of the cancer.
  • Local transanal resection —Removal of the cancer with a margin of surrounding healthy tissue.
  • Transanal endoscopic microsurgery (TEM) —Removal of the cancer in the rectal wall with surrounding healthy tissue; the hole in the wall is sewn back together.
  • Low anterior resection —Removal of the cancer, surrounding healthy tissue, and lymph nodes for cancers high in the rectum, closer to the colon.
  • Proctectomy —Removal of the rectum; this surgery also involves attaching the end of the colon to the anal canal in order to preserve bowel function.
  • Abdominoperineal resection —Removal of rectum, anal canal, and surrounding tissue.
  • Pelvic exenteration —Removal of rectum, anal canal, and nearby organs with cancer, such as the prostate, uterus, or bladder.

Some surgeries may require temporary or permanent colostomies. A colostomy is a surgical opening through the wall of the abdomen into the colon. This is used as a path for waste material to leave the body. After a colostomy, you will wear a special bag to collect body waste. If the bladder is removed, you will also need a urostomy. A urostomy is an opening in the abdominal wall that allows for the passage of urine.

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    TOP

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.

Medications    TOP

Targeted Therapy

Targeted therapy uses medications to target and kill cancer cells, while sparing healthy tissue. They are currently used to treat advanced cancers. Targeted therapy is less harmful to healthy tissue, which reduces side effects. It may be used alone or in combination with chemotherapy.

Other Medications

Some medications can be used as part of a treatment plan. Other medications may help to either prevent or reduce side effects of treatments, or to manage certain side effects if they occur. These include:

  • Corticosteroids
  • Blood stem cell support medications
  • Antiemetics to control nausea
  • Nonsteroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen
  • Prescription pain relievers

Prevention    TOP


The causes of most cancers are not known. However, it is possible to prevent many colon and rectal cancers by finding and removing polyps that could become cancerous. Beginning at age 50, both men and women at average risk should follow one of the following screening options:

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

  • African Americans or Native Americans
  • History of colon or rectal cancer, or adenomatous polyps
  • Strong family history of colon or rectal cancer or polyps
  • Family history of hereditary colon or rectal cancer syndromes
  • History of chronic inflammatory bowel disease

Be sure to discuss colon cancer screening with your doctor to see how and when you should be screened.

Lifestyle Changes

Lifestyle changes that may reduce your risk of rectal cancer:

  • If you smoke, talk to your doctor about ways to quit
  • Drinking alcohol in moderation—no more than 2 drinks a day if you are a man, and no more than 1 drink a day if you are a woman
  • Eating a healthful diet high in fruits, vegetables, and whole grains, and low in red meat
  • Being physically active by exercising at least 30 minutes a day on most days of the week
  • Maintaining a healthy weight


American Cancer Society
National Cancer Institute


Canadian Cancer Society
Colorectal Cancer Association of Canada


Colorectal cancer. American Cancer Society website. Available at:
...(Click grey area to select URL)
Updated April 28, 2015. Accessed September 6, 2016.
Colorectal cancer. EBSCO DynaMed Plus website. Available at: Updated August 18, 2016. Accessed September 6, 2016.
Colorectal cancer screening tests. American Cancer Society website. Available at:
...(Click grey area to select URL)
Updated June 24, 2016. Accessed September 6, 2016.
General information about rectal cancer. National Cancer Institute website. Available at:
...(Click grey area to select URL)
Updated June 30, 2016. Accessed September 6, 2016.
Rex DK, Johnson DA, Anderson JC, et al. American College of Gastroenterology guidelines for colorectal cancer screening 2009. Am J Gastroenterol. 2009;104(3):739-750.
11/19/2010 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.
4/8/2014 DynaMed's Systematic Literature Surveillance. Yee J, Kim DH, Rosen MP, et al. Colorectal cancer screening. American College of Radiology (ACR) Appropriateness Criteria. Available at:
...(Click grey area to select URL)
Updated 2013. Accessed September 6, 2016.
Last reviewed May 2016 by Mohei Abouzied, MD
Last Updated: 5/27/2014

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This content is reviewed regularly and is updated when new and relevant evidence is made available. This information is neither intended nor implied to be a substitute for professional medical advice. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with questions regarding a medical condition.

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