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Rectal Cancer 

Rectal cancer is cancer that develops in the rectum.  The rectum is the last six inches of the large intestine.  Bleeding and a change in bowel patterns are common symptoms of rectal cancer.  Most rectal cancers are treated with surgery and radiation therapy, chemotherapy, or both.

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The first part of the colon absorbs water and nutrients from the waste products that come from the small intestine.  As the colon absorbs water from the waste product, the product becomes more solid and forms a stool or feces.  The large intestine moves the stool through the large intestine into the sigmoid colon, where it may be stored before traveling to the rectum.  The rectum is the final 6-inch section of your large intestine which stores stool.  No significant nutrient absorption occurs in the rectum or anal canal.  From the rectum, the stool moves through the anal canal.  It passes out of your body through your anus when you have a bowel movement. 

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The exact cause of rectal cancer is unknown.  Cancer occurs when cells in the interior lining of the rectum grow abnormally and out of control, instead of dividing in an orderly manner.  Increasing age and a family history of rectal, colon, or certain other cancers appear to increase the risk of rectal cancer.

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Hallmark symptoms of rectal cancer include a change in bowel habits and blood in the stool.  The blood may be bright red or very dark.  Your stools may change shape and be narrower than usual.  You may have diarrhea, vomiting, or constipation.  It may feel like your bowel does not completely empty when you go to the bathroom.  You may experience frequent gas, bloating, fullness, or cramps.  You may feel tired all of the time and lose weight without trying.

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You should contact your doctor if you experience the symptoms of rectal cancer.  Other non-cancerous conditions may have symptoms similar to rectal cancer, but you need to have your doctor make that determination.  Rectal cancer that is diagnosed and treated early is associated with the best outcomes.
Your doctor will review your medical history.  It is important to tell your doctor about your risk factors and symptoms.  Your doctor will conduct a rectal examination to detect abnormal masses or growths.  Your doctor may use other evaluations to help diagnose your condition.
A stool blood test can detect small amounts of blood in your stool.  The fecal occult blood test (FOBT) or the fecal immunochemical test (FIT) is commonly used.  You will receive a kit and instructions for taking a stool sample at home.  The kit is sent to a laboratory for testing.  If the test results are positive, your doctor will order a sigmoidoscopy or colonoscopy to identify the exact cause of bleeding.
A flexible sigmoidoscopy is used to view the rectum and part of the colon for cancer or polyps.  A sigmoidscope is a thin tube with a light and viewing instrument.  It is about two feet long.  The sigmoidscope is placed in the colon, through the rectum.  This test can be uncomfortable, but should not be painful.
A colonoscopy is used to view the entire colon.  A colonoscope is similar to a sigmoidoscope, but it is much longer.  A colonoscope allows a doctor to examine the colon for cancer or polyps.  A tissue sample or biopsy may also be taken with the colonoscope.  A colonoscopy can be uncomfortable, and you will receive medication to relax you prior to the test.
A lower gastrointestinal (GI) series or barium enema test provides a series of X-ray images of the rectum and large intestine.  A barium enema is commonly used to screen for cancer and bowel diseases.  Prior to taking X-rays, barium, a chalky substance, and air are used to fill and expand the intestine.  The barium reveals the bowel’s shape and position on the X-ray images.  A barium enema is an outpatient procedure that is performed at a doctor’s office or a hospital’s radiology department. 
If you have rectal cancer, your doctor will assign your cancer a classification stage based on the results of all of your tests.  Staging describes the cancer and how it has metastasized.  Staging is helpful for treatment planning and recovery prediction. 
There is more than one type of staging system for cancer, and you should make sure that you and your doctor are referring to the same one.  Generally, lower numbers in a classification system indicate a less serious cancer, and higher numbers indicate a more serious cancer.  The stages may be subdivided into grades or classifications that use letters and numbers.

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Rectal cancer is treated with surgery, radiation therapy, chemotherapy, or a combination of treatment types.  The type of treatment that you receive may depend on several factors, including the stage of your cancer and your general health.  Surgery is the most common treatment for rectal cancer. 

A local excision may be used to remove rectal cancer that is found very early.  For instance, a polyp may be removed from the rectum without cutting into the abdomen.  A local resection is a procedure that is used to remove the cancer and the tissue around it.  A local resection usually leaves the anus sphincter intact, and following surgery you will be able to have bowel movements.  A resection and colostomy may be necessary if the rectum cannot be sewn back together again.  A stoma, opening at the side of the body, is created for waste products to move through, which are collected in a colostomy bag.  With a colostomy, you will not be able to have bowel movements as you did before.

Radiation therapy uses high-energy rays to destroy cancer cells.  External radiation or internal radiation therapy may be used to treat rectal cancer.  External radiation delivers radiation from an external source, a machine.  Internal radiation therapy, brachytherapy, involves implanting radioactive seed pellets in or near the cancer.  The seeds deliver a slow dose of radiation.  Internal radiation methods may also use radioactive wires, needles, or catheters.  The type of radiation that you receive depends on the type of cancer that you have.

Chemotherapy uses cancer fighting drugs or combinations of drugs to kill cancer cells.  You may receive chemotherapy in the form of pills or they may be injected through a needle.  Chemotherapy may be used in combination with radiation therapy or after surgery to destroy any remaining cancer cells.

Even with treatment, some cases of rectal cancer may return.  This is termed “recurrent rectal cancer.”  Your doctor can explain your risk for rectal cancer and possible treatments if it does recur.

The experience of rectal cancer and cancer treatments can be an emotional process for people with cancer and their loved ones.  It is important that you receive support from a positive source.  Some people find comfort in their family, friends, counselors, co-workers, and faith.  Cancer support groups are another good option.  They can be a source of information and support from people who understand what you are experiencing.  Ask your doctor for cancer support group locations in your area.

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You should contact your doctor as soon as you experience the symptoms of rectal cancer.  Rectal cancer that is diagnosed and treated early is associated with the best outcomes.

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Am I at Risk

Risk factors may increase your likelihood of developing rectal cancer, although some people that develop rectal cancer do not have any risk factors.  People with all of the risk factors may never develop the disease; however, the chance of developing rectal cancer increases with the more risk factors you have.  You should tell your doctor about your risk factors and discuss your concerns.

Risk factors for rectal cancer:

_____ People that are 50 years old and older have a higher risk for rectal cancer.
_____ People with a family history of colon or rectal cancer have a higher risk of rectal cancer.
_____ People that have experienced colon, rectal, ovary, endometrium, or breast cancer have a higher risk of rectal cancer.
_____ People with inflammatory bowel disease have an increased risk of developing rectal cancer.
_____ Select hereditary conditions increase the risk for rectal cancer.  Conditions include familial adenomatous polyposis and nonpolyposis colon cancer.

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Rectal cancer may spread to other parts of the body, including the lungs, liver, and ovaries.  Rectal cancer may recur after it has been treated. 

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Biological therapies are being tested as a treatment for rectal cancer in clinical trials.  Biological therapy works to stimulate the body’s immune system to fight cancer.  Biological therapy is sometimes called immunotherapy.  Rectal stents are also being used to treat the symptoms of cancer to give people a better quality of life.  Non-surgical endoscopic methods called endoscopic mucosal resection (EMR) are being tested for some types of rectal cancer.

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This information is intended for educational and informational purposes only. It should not be used in place of an individual consultation or examination or replace the advice of your health care professional and should not be relied upon to determine diagnosis or course of treatment.

The iHealthSpot patient education library was written collaboratively by the iHealthSpot editorial team which includes Senior Medical Authors Dr. Mary Car-Blanchard, OTD/OTR/L and Valerie K. Clark, and the following editorial advisors: Steve Meadows, MD, Ernie F. Soto, DDS, Ronald J. Glatzer, MD, Jonathan Rosenberg, MD, Christopher M. Nolte, MD, David Applebaum, MD, Jonathan M. Tarrash, MD, and Paula Soto, RN/BSN. This content complies with the HONcode standard for trustworthy health information. The library commenced development on September 1, 2005 with the latest update/addition on April 13th, 2016. For information on iHealthSpot’s other services including medical website design, visit