A colonoscopy is done to check for colon cancer or other conditions that affect your colon. It’s not used to check for prostate cancer.

A colonoscopy is a diagnostic test that’s done by inserting a thin, lighted tube and a camera through your rectum to look inside your large intestine — also known as your colon. It’s often used to check for conditions that affect your colon, such as:

Screening tests for prostate cancer are much different. A medical professional will usually screen for prostate cancer using a prostate-specific antigen (PSA) blood test and a digital rectal exam (DRE). They may also use imaging tests to look for growths or abnormalities.

Read on to learn the differences between a colonoscopy and prostate cancer screenings and when you’ll need each type of test.

Language matters

You’ll notice that the language used to share stats and other data points is pretty binary with the use of “men.”

Although we typically avoid language like this, specificity is key when reporting on research participants and clinical findings.

Unfortunately, the studies and surveys referenced in this article didn’t report data on, or include, participants who were transgender, nonbinary, gender nonconforming, genderqueer, agender, or genderless.

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For most people, a colonoscopy is a routine diagnostic test that’s done to check for early signs of colorectal cancer that can affect your large intestine and your rectum.

A colonoscopy is an outpatient procedure that usually takes about 30 minutes. Here’s a quick overview of what to expect during a colonoscopy:

  1. You’ll change into a hospital gown and lie on your side on an operating table with your knees near your chest.
  2. You may be given either light sedation or a general anesthetic to keep you comfortable or asleep during the procedure.
  3. The doctor slowly inserts a lighted tube with a camera through your anus and rectum into your colon. They’ll inflate your colon with carbon dioxide to widen the space inside and get better images.
  4. The doctor views live images on an external screen as the camera moves through your colon.
  5. If needed, the doctor can take out any polyps or a tissue sample that can be tested for cancer.

A PSA test checks for prostate cancer. This blood test shows whether you have high levels of PSAs, which is a common early sign of prostate cancer.

The next step is a DRE to feel around the prostate gland for changes in the gland’s size or for growths such as tumors. If a doctor believes you may have cancerous prostate tumors, you may need further imaging to look more closely at the prostate and the surrounding tissues.

A DRE is also an outpatient procedure. Here’s how it’s done:

  1. You’ll change into a hospital gown and lie on a table on your side or in a position that’s comfortable for you, such as squatting or bending over the table.
  2. A doctor puts on a clean glove and lubricates one of their fingers to make it more comfortable to slide the finger in your anus.
  3. The doctor slowly and gently inserts their lubricated finger into your anus to feel the prostate gland and the tissues nearby, checking for growths or abnormalities.
  4. The doctor removes their finger, and you can get changed back into your clothes.

If the doctor finds any abnormalities, they may recommend that you get imaging tests done to look for tumors or rule out an enlarged prostate as a cause.

According to the Centers for Disease Control and Prevention (CDC), you should get a colonoscopy at least once every 10 years if you:

In addition to meeting these criteria, you might need a colonoscopy if:

A doctor may recommend a colonoscopy if you’re at a high risk of colon cancer, even if you haven’t reached the recommended age range.

The CDC also notes that the following men should discuss their situation with a healthcare professional and decide whether they should be screened or have a DRE:

  • are between 55 and 69 years old
  • have a normal or above average risk of prostate cancer
  • have direct relatives who have gotten prostate cancer

A DRE can also be done to:

  • check for tumors in your rectum
  • check for prostate infections
  • get a sample for a fecal occult blood test for bleeding or cancer
  • check your sphincter if you’re experiencing fecal incontinence
  • check for hemorrhoids
  • diagnose causes of bleeding from your rectum

A colonoscopy can be uncomfortable due to the carbon dioxide used to inflate your colon and pain from the removal of polyps or tissue.

You also need to empty out your bowels before a colonoscopy. This requires drinking specific fluids and eating a specific diet. Having recent bowel movements for several hours before a colonoscopy can be uncomfortable and exhausting.

A DRE doesn’t usually cause any pain if it’s done correctly. The feeling of a finger in your anus can be uncomfortable, but the procedure is quick and won’t leave any residual pain of discomfort.

A colonoscopy is done to check for colon cancer or other conditions that affect your colon. A PSA test and DRE are commonly used as prostate cancer screening tests.

Try to speak with a medical professional if you’re concerned about colon cancer or prostate cancer to decide the next steps you should take to seek a diagnosis and treatment.