Overview of Sigmoidoscopy Test | Oncology


What is a sigmoidoscopy?

Sigmoidoscopy is a diagnostic test used to examine the sigmoid colon, which is the lower part of your colon or colon. This section of your colon is closer to your rectum and anus.

Sigmoidoscopy can help diagnose the following symptoms:

  • Diarrhea
  • Abdominal pain
  • Constipation
  • Polyps (abnormal growth)
  • Bleeding

Sigmoidoscopy can also be used to take a tissue sample or a biopsy. And it can be used to remove polyps or hemorrhoids (swollen veins in the rectum and anus). It is a screening test for colon cancer and rectal cancer.

Sigmoidoscopy is done using a thin, flexible tube called a sigmoidoscopy. The tube contains a small light and a camera. The tube is placed in your anus and is slowly moved through your rectum to the lower part of your colon. The tube is used to blow air into the colon, causing the colon to swell slightly to improve visibility.

Sigmoidoscopy, also known as flexible sigmoidoscopy, is a procedure that allows you to see your doctor using a flexible tube that contains light inside your sigmoid colon. It is useful to consult with your doctor:

  • Ulcers
  • Abnormal cells
  • Polyps
  • Cancer

Usually, the tissue fragments are sampled to check for abnormal cell changes.

Why do I need a sigmoidoscopy?

Sigmoidoscopy can be used to examine or diagnose certain conditions or structures in the lower part of the colon, including:

  • Polyps
  • Tumors
  • Ulcers (sores)
  • Inflammation (redness and swelling)
  • Hemorrhoids
  • Diverticula (wallets on the wall of your colon)
  • Difficulties (narrowing of your lower colon)
  • It can also be used to investigate the following:
  • Changes in your bowel habits.
  • Pain in the lower abdominal area
  • Itching around your anus
  • Blood or mucus in the stool
  • Low iron levels
  • Low blood counts

Sigmoidoscopy is a type of test used to detect colon and rectal cancers. Health experts recommend that both men and women follow a colon and rectal cancer screening program beginning at age 50. Talk to your healthcare provider about a screening schedule that works for you. There are many screening options available for colon cancer.

There may be other reasons for your healthcare provider to recommend sigmoidoscopy. If the sigmoidoscopy shows polyps, a colonoscopy may be recommended as the next step to examine the rest of the colon.

Purpose of sigmoidoscopy

Sigmoidoscopy is used to diagnose certain intestinal problems such as unexplained bleeding, diarrhea, constipation, or rectal pain. If your doctor sees a suspicious area, he or she can remove a piece of tissue using an attachment at the end of the sigmoidoscope and send it to the lab for examination under a microscope. This is called a biopsy. If your doctor finds an abnormal area during the test, he or she may recommend a more comprehensive test called a colonoscopy.

Sigmoidoscopy is also used as a screening test to detect colorectal cancer. It usually happens once every 5 years, starting at age 50. This can be combined with a fecal occult blood test to look for cancer in the upper part of the colon. Alternatively, your doctor may recommend colonoscopy for cancer screening, usually once every 10 years for those at average risk. 

Risk factors for sigmoidoscopy

The following complications can occur after sigmoidoscopy:

  • The bleeding continued after the biopsy
  • Inflammation of the lining of the abdomen (peritonitis)
  • A perforation (hole) in the intestinal wall, which is a rare problem

The following complications or conditions can interfere with sigmoidoscopy:

  • Use laxative enemas before the test, as they can irritate the lining of the colon
  • There is barium in your colon from another recent test that was used to check your colon
  • Bowel preparation before the procedure is inadequate
  • Complications that limit tube movements, such as stiffness, adhesions (surgical scars), or chronic inflammatory disease
  • Rectal bleeding, which limits visibility.

You may have other risks that are unique to you. Discuss any problems with your healthcare provider before the procedure.

When is sigmoidoscopy performed?

You should inform your doctor if you notice:

  • Changes in your bowel habits.
  • Rectal bleeding
  • Abdominal pain
  • Unexplained weight loss

These can be signs of various diseases of the colon, and sigmoidoscopy can be a procedure that can help determine the cause of your symptoms. Sigmoidoscopy is a common screening tool for colon cancer.

Depending on your personal medical history and if your family has a history of colorectal cancer, you should have a sigmoidoscopy every five years after age 50.

How should I prepare for sigmoidoscopy?

Your healthcare provider will fully explain this process and answer your questions. You will be asked to sign a consent form prior to the test. Please read the form carefully and ask any questions you may have. Before your policy, be sure to tell your healthcare provider:

  • If you are pregnant or think you may be
  • If you are sensitive or allergic to any medications, latex, tape, or anesthetics (local and general)
  • About all the medicines you take, including over-the-counter drugs, prescription drugs, vitamins, herbs, and other supplements.
  • If you have a history of bleeding disorders
  • If you are taking medications to thin the blood, aspirin, ibuprofen, or other medications that affect blood clotting; These medications must be stopped before the procedure.

Your healthcare provider will give you instructions on how to prepare your bowel for the test. You may be asked to take a laxative, enema, or laxative suppository. Or you may need to drink a special liquid to help prepare your intestines. You will be given specific instructions about fasting (not eating) or following a special diet prior to the test.

Follow the instructions your provider gave you to prepare for your sigmoidoscopy.

Preparing for sigmoidoscopy

Preparing for your sigmoidoscopy is equivalent to preparing for your colonoscopy. You should use one or more enemas about two hours before the procedure.

If the entire colon needs to be emptied, preparing for what you do for the colonoscopy is even more so. For example, follow a clear liquid diet for one to three days before the procedure. You may be given a powdered laxative to mix with the liquid to help empty your intestines. The fluids you consume include:

  • Simple coffee or tea
  • Of water
  • Fat-free broth
  • Gelatin, like gel-o
  • Sports drinks with electrolytes

You may want to avoid liquids with red or pale color because it looks like blood in the colon.

Before the procedure, inform your doctor about any medical conditions you may have and all medications and medications you are taking.

What happens during sigmoidoscopy?

A sigmoidoscopy may be done in the fundus or it may be part of a hospital stay. The way the test is performed may vary depending on your condition and the practices of your healthcare provider. You usually do not need a sedative (to relax you) or anesthesia (to achieve a sound sleep) before the exam.

Before the procedure, you will be asked to remove jewelry or other items that may interfere with the procedure. You may be asked to remove your clothing and change it into a hospital gown.

To get you into the correct position, you may be asked to bend your knees toward your chest on the exam table to your left. Or you can place him in a knee-to-chest position, with his head and chest bent, touching the table.

Sigmoidoscopy procedure

Generally, sigmoidoscopy follows this procedure:

Your provider will do a stool test to check for blood, mucus, or stool. He or she gently spreads (expands) your anus.

Your provider will slowly insert a lubricating tube into your anus and move it through your rectum to the lower part of your colon. After inspecting the lower part of your colon, the tube is removed.

Air can be injected into your intestine to improve visibility. A suction device can be used to remove liquid stool.

Sigmoidoscopy may be done in conjunction with an anoscopy (a test that examines your anus) or a proctoscopy (the test that examines your anus and rectum). If another test is done, a special tube is inserted to check the lower rectum or anal canal.

Sigmoidoscopy may cause mild discomfort. You want to have a bowel movement when the tube is inserted. You may also have brief muscle aches or lower abdominal pain during the test. Breathing deeply while the tube is inserted can help reduce pain.


During the test, biopsies (tissue samples) may be taken from the lining of your large intestine. This can be done with a special brush, forceps, or swab. If a polyp appears, it can be removed, biopsied, or left alone until future surgery.

What happens after sigmoidoscopy?

You should lie on your side or on your back for a few minutes before getting up from the table. Move slowly while standing. This will help you feel less dizzy without lowering your head during the test.

You can return to your normal diet and activities unless your doctor gives you other instructions.

If a biopsy or polyp is removed during the test, you may see a small amount of blood in your stool. This bleeding should stop in a day.

It is common for patients to have a lot of farting (passing too much gas) and gas pains after the test. Walking and rolling over can help ease any minor pain.

If you experience any of the following, call your healthcare provider:

  • Fever or cold
  • Bleeding from the rectum lasts more than a day
  • Abdominal pain or swelling
  • Inability to pass gas

Your healthcare provider can give you other directions related to your specific condition.

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