Colonoscopy is a common procedure that’s used to diagnose and monitor conditions affecting your colon and rectum. It can be used to detect conditions like colorectal cancers and precancers, IBD, and diverticulitis.

A colonoscopy is a procedure in which a healthcare professional uses a flexible tube with a camera on the end to view the inside of your colon and rectum. Over 15 million colonoscopies are done in the United States each year.

Your healthcare professional can use a colonoscopy to help diagnose and monitor a variety of health conditions that affect your colon and rectum.

A colonoscopy can be used to detect several different conditions. Let’s explore some of these briefly now.

Cancer

Many of us encounter a colonoscopy as a part of colorectal cancer screening. Colorectal cancer is the third most common cancer in both men and women in the United States, as well as a leading cause of cancer death.

Colorectal cancer typically starts as a lesion in the large intestine called a polyp. A colonoscopy can be used to locate these polyps.

Any polyps found during a colonoscopy can be removed and tested in a lab to see if they’re benign (not cancerous), pre-cancerous, or malignant (cancerous).

Colonoscopy can help prevent colorectal cancers. For example, one 2022 trial found that, compared to those who didn’t receive a colonoscopy, those who did had an 18% decreased risk of colorectal cancer at 10 years.

Inflammatory bowel disease

Inflammatory bowel disease (IBD) refers to diseases that lead to chronic inflammation in the digestive tract. Two common types of IBD are ulcerative colitis and Crohn’s disease.

A colonoscopy can be used to help diagnose IBD. Researchers estimate that a thorough evaluation using endoscopic techniques like colonoscopy can lead to a correct IBD diagnosis 89% of the time.

A healthcare professional can use a colonoscopy to look for areas of inflammation or ulcers along the colon and rectum. A biopsy sample can also be taken during a colonoscopy and analyzed in a lab to help make a diagnosis.

It’s also possible that colonoscopy may be used to monitor IBD response during treatment.

Other bowel conditions

In addition to cancer and IBD, colonoscopy can also be used to detect other bowel conditions. These include:

  • diverticulitis, a condition where small pouches form in the walls of your colon
  • bowel obstruction, in which the large intestine has become blocked due to things like scar tissue, inflammation, foreign objects, or tumors
  • ulcers not associated with IBD, such as those due to infections or medications

While a colonoscopy can detect a variety of conditions, there are some conditions it cannot detect.

For example, a colonoscopy cannot detect irritable bowel syndrome (IBS), a digestive condition that causes abdominal pain, diarrhea, and constipation.

Additionally, because a colonoscopy only looks at your colon and rectum, it cannot be used to detect conditions affecting other parts of your body, such as your stomach, small intestine, pancreas, or gallbladder.

A colonoscopy is often used to screen for colorectal cancer. The American Cancer Society recommends that adults at an average risk of colorectal cancer begin screening at age 45.

There are several test options available to screen for colorectal cancer, one of which is a colonoscopy. A colonoscopy can be done every 10 years to check for cancer.

Other reasons that a colonoscopy may be recommended are if you’re having symptoms like:

In order for your colonoscopy to proceed safely, you’ll need to tell your healthcare professional about several things beforehand. These include any medications or supplements you’re taking as well as known allergies or other health conditions.

Prior to your colonoscopy, you’ll also need to do a bowel prep. This allows your large intestine to be empty and clean so that your healthcare professional can clearly see its lining during the colonoscopy.

You’ll be given instructions on foods to eat and avoid in the time leading up to your colonoscopy. Examples include avoiding high fiber foods and sticking to clear liquids. A bowel prep also typically involves the use of laxatives, which can lead to diarrhea.

A colonoscopy is done while you’re awake. However, you’ll be given a sedative so that you feel sleepy and relaxed while it’s being done.

You’ll be instructed to lie on a table with your knees pulled to your chest. Your healthcare professional will carefully guide the colonoscope into your anus. Small amounts of air are used to help them get a better view.

The camera on the end of the colonoscope shows your healthcare professional the lining of your large intestine. In some cases, a polyp or tissue sample will be removed so that it can be tested in a lab.

After your healthcare professional has examined all of your colon and rectum, they’ll carefully remove the colonoscope. Typically, a colonoscopy takes less than 1 hour.

Overall, a colonoscopy is a safe procedure. However, it’s still possible for complications to occur, although these are rare.

The potential risks and complications of a colonoscopy are:

After your colonoscopy, healthcare staff will monitor you as your sedation wears off. Since you’ve been sedated, you’ll need someone to drive you home from your procedure.

It’s normal to have some side effects after a colonoscopy, such as cramping or bloating. If polyps were removed or a biopsy was taken, you may also have some light bleeding from your rectum.

You should generally be recovered and ready to return to your regular diet the next day. Any testing results will typically be available within a few days. Your healthcare professional will follow up with you to discuss them.

A colonoscopy can be used to detect a variety of conditions impacting your colon and rectum. These include colorectal cancers and pre-cancers, IBD, diverticulitis, and bowel obstructions.

You typically receive a colonoscopy as an outpatient and can return to your typical activities and diet the next day. Complications from colonoscopy are rare.

See your healthcare professional if you have symptoms like blood in your stool, changes in bowel habits, or unexplained abdominal pain. A colonoscopy may be recommended to help determine what’s causing these symptoms.