What is the difference between a prostate exam and a colonoscopy?

Share on Pinterest

A prostate exam is a medical procedure to screen for prostate cancer. Prostate exams are only for people who have a prostate since people without a prostate cannot develop prostate cancer.

According to the Prostate Cancer Foundation (PCF), the exam may involve two tests: a prostate-specific antigen (PSA) test and a digital rectal examination (DRE).

PSA test

The prostate produces a protein called PSA. According to the Centers for Disease Control and Prevention (CDC), increased levels of PSA in the blood can be a sign of prostate cancer or other prostate conditions.

A PSA test measures levels of PSA in the blood. Typically, higher levels of PSA indicate an increased likelihood of prostate issues.

The American Cancer Society (ACS) states that doctors measure blood levels of PSA in nanograms per milliliter (ng/mL). There is no specific cutoff point for determining whether an individual has prostate cancer. However, many doctors will use a cutoff of 4 ng/mL or above, while others may use a cutoff of 3 ng/mL or even 2.5 ng/mL or above.

DRE

The DRE is a physical examination in which a doctor inserts a lubricated finger into the rectum to check for abnormalities with the prostate gland.

DREs are less effective at detecting prostate cancer compared to PSA testing. However, a DRE can sometimes detect cancer in individuals who have normal PSA levels. As such, doctors may include this test as part of a prostate exam.

According to the American College of Gastroenterology (ACG), a colonoscopy is a procedure that allows doctors to view and examine the colon. It can help in diagnosing a range of gastrointestinal (GI) disorders, including colon cancer and colon polyps.

A colonoscopy involves inserting a long, flexible tube or “colonoscope” into the rectum and up into the colon. The tube has a camera attached, allowing doctors to view the entire length of the colon.

Colonoscopies are for both sexes since males and females have an equal risk of developing colon cancer.

A prostate exam and a colonoscopy can help doctors diagnose conditions in different parts of the body.

Prostate exam

A prostate exam can help doctors screen for and diagnose prostate cancer or other prostate conditions.

Colonoscopy

According to the ACG, a colonoscopy can help doctors diagnose a range of gastrointestinal (GI) disorders, including:

• colon cancer
• colon polyps
• diverticulitis
• inflammatory bowel disease
• intestinal obstruction

Below is the procedure for prostate exams versus colonoscopies.

Prostate exam

To perform a prostate exam, a doctor inserts a gloved, lubricated finger into the rectum to check for abnormalities on the prostate.

Due to the positioning of the prostate, the doctor will only be able to detect abnormalities toward the back of the prostate gland. However, prostate cancers often develop in this area.

A prostate exam can be uncomfortable, particularly for individuals who have hemorrhoids. However, the exam should not be painful.

Colonoscopy

A colonoscopy involves inserting a colonoscope into the rectum and up into the colon.

A camera attached to the colonoscope allows doctors to view the entire length of the colon and assists them in making a diagnosis.

If necessary, doctors can insert specialist instruments into the colonoscope to take biopsies or remove colon polyps, which could otherwise develop into cancer.

The following outlines the screening guidelines for prostate exams and colonoscopies.

Prostate exam

The PCF recommends individuals with a prostate begin prostate screening at age 45, while individuals with an increased risk of developing prostate cancer begin screening earlier at age 40.

Colonoscopy

The ACG recommends everyone receive their first colonoscopy screening at age 45.

For individuals at increased risk of developing colon cancer, the ACG recommends colonoscopy screenings starting at age 40, or 10 years before the age of their youngest family member developed colon cancer — whichever is earliest.

Below are some answers to frequently asked questions about prostate exams and colonoscopies.

Can a colonoscopy detect prostate problems?

A colonoscopy cannot detect issues with the prostate. However, an older 2009 study notes doctors typically perform a DRE before a colonoscopy, and the DRE can help detect prostate cancer in males.

Can a colonoscopy include a prostate exam?

Before inserting the camera for a colonoscopy, doctors typically perform a DRE on everyone undergoing the procedure to check for any potential lesions, masses, or atypical anatomy. If the person receiving the colonoscopy is male, the doctor may incorporate a prostate exam into the DRE.

Which is more accurate for prostate cancer?

A prostate exam is a more accurate method for detecting prostate cancer.

The exam consists of two assessments: PSA testing and a DRE. Of these two assessments, PSA testing is the most accurate test for prostate cancer. However, DREs can sometimes detect prostate cancer in individuals with normal PSA levels.

A prostate exam helps detect prostate cancer in people who have a prostate gland, while a colonoscopy helps detect colon cancer and other gastrointestinal (GI) conditions in both males and females.

A prostate exam may include two procedures — a prostate-specific antigen (PSA) test and a digital rectal examination (DRE). A colonoscopy involves using a colonoscope to view the inside of the colon. Doctors may sometimes perform a DRE before a colonoscopy, especially if the person has a prostate gland.

Most people with a prostate should begin prostate screening at age 45, whereas both men and women should receive their first colonoscopy at age 45. Individuals with risk factors for either disease should begin the appropriate screening procedure at age 40 or younger. A person can talk with a doctor if they require further advice about prostate or colonoscopy screening.