When it comes to detecting colorectal cancer, there are two prominent tools that are used: the traditional colonoscopy vs. Cologuard, an at-home test that many have turned to in order to avoid a colonoscopy. Although both methods share the common goal of identifying irregularities in the colon, such as colon polyps, they each have advantages and disadvantages, along with limitations, especially when it comes to the Cologuard test.
Understanding the differences between colonoscopy vs Cologuard is vital to choosing the right tool to help prevent colon cancer.
When to Get Screened for Colon Cancer
Colon cancer is a type of cancer that develops in the colon or rectum. It usually begins as small, pre-cancerous growths called polyps on the inner lining of the colon or rectum, and over time these polyps can become cancerous. Early stage colon cancer often does not have symptoms; symptoms may appear in later stages consisting of: changes in bowel habits, blood in the stool, abdominal pain, fatigue, and unexplained weight loss. Cure rates are much lower when patients have symptoms so having a screening evaluation is imperative.
Because colon cancer may not show any symptoms, it’s important to get screened for it per the guidelines, as early detection increases the chance for successful treatment. The current recommendation is that individual start screening for colon cancer at age 45. However, colon cancer is appearing in younger individuals, and you may need to get tested earlier if you have a family history or personal history of colon cancer or polyps, IBD, a history of rectal or anal bleeding or a genetic condition.
What Are the Different Types of Colon Cancer Screening Tools?
While a colonoscopy is the gold standard of all of the tests and the most recommended way to screen for colon cancer, there are a few different types of tool used. Stool based tests look at the stool with chemicals and visual tests look directly at the colon. Other tests beside colonoscopy include CT colonography, flexible sigmoidoscopy Cologuard and FIT stool test.Visual tests include a cat scan colonography, a sigmoidoscopy and a colonoscopy. CT colonography and a colonoscopy require a colon cleanse while the flexible sigmoidoscopy only requires a fleet enema. A CT colonography test can identify polyps and cancer, however; no biopsies or polyp removal procedures can be performed like a colonoscopy or flexible sigmoidoscopy. I do not perform flexible sigmoidoscopies as a colonoscopy is more complete.
Stool based tests include Cologuard and the FIT stool test. Cologuard uses stool samples to look for possible signs of colorectal cancer or polyps. Patients put the stool into a kit and send it to the company for evaluation of the stool. The test looks for microscopic blood and altered DNA.
Another type of stool test is called a FIT kit. Patients take a sample of the stool and a kit shows if there is blood in the stool. Many people prefer to use stool sample tests because they can be done at home and there is little preparation needed. There are many benefits to doing visual tests, though, including more accuracy, even if there is more preparation involved.
What is a Colonoscopy?
One of the best methods to screen for colon cancer is to have a colonoscopy as your proctologist can see the entire colon and make sure there aren’t any small signs of cancer that other tests may not pick up on.
During a colonoscopy, a slender flexible tube with a camera and light at its tip is gently inserted through the rectum and guided through the entire length of the colon. The real-time images allow your doctor to examine the colon’s lining for any sign of tumors, polyps, inflammation, or bleeding. Many people tend to be fearful of colonoscopies because they worry about discomfort, the bowel preparation, risks of bleeding or perforation of the colon and anesthesia. The risks are very small and the procedure is very safe. To lower the risk of anesthesia, I have an anesthesiologist perform the sedation.
The advantage of the colonoscopy is the ability to remove polyps, biopsy lesions and detect inflammation.
Before a colonoscopy, patients will need to perform a bowel prep, which includes following a specific diet and taking laxatives to cleanse the colon prior to the procedure. Although bowel preparation can be difficult for some people, it’s important to do it in order to get a clear view of the colon during the exam.
What is Cologuard?
Cologuard is a stool test that is used for screening for colon cancer. It examines cells shed from the colon that are in the stool for any abnormal cells or blood found in the test it may indicate cancer or precancer tumors. Cologuards are recommended for people between the ages of 50 to 75 years, once every three years.
Unlike a colonoscopy, patients do not need to prepare for the stool test. Patients collect the stool per the instructions that come with the kit. The ease of the test appeals to patients who are deciding between colonoscopy vs cologuard, especially those who may have had issues with surgeries and exams in the past.
Colonoscopy vs Cologuard: Which is Better?
When it comes to a colonoscopy vs cologuard, proctologists and other doctors recommend colonoscopies. They are the gold standard for detecting colon cancer and other colon irregularities.
Colonoscopies can detect up to 95% of large polyps and cancer, whereas Cologuard is shown to detect only 42% of large polyps and 95% of cancers. If the Cologuard test is abnormal, you will need to follow-up with a colonoscopy to look for polyps or cancer. Therefore, Cologuard is a very good test at detecting cancer and poor for detecting polyps which may lead to cancer. A colonoscopy has been proven to lower the risk of colorectal cancer deaths by 53%.
A great screening test is meant to find precancerous changes like a polyp and Cologuard does not do this well. We want to find pre-cancerous changes to prevent cancer, not wait until cancer appears and then detect the cancer. A colonoscopy will find both polyps and cancer up to 95% of the time.
Another disadvantage of the Cologuard test is that the results are indicated as “positive” or “negative”. Positive tests indicate the test found something abnormal but it can’t say if it was a little blood in the stool, a polyp or cancer. During a colonoscopy, if the doctor finds a polyp, they can remove it during the procedure, which eliminates the need for any additional tests.
Cologuard, though, is designed to detect a polyp or cancer, not prevent it, unlike a colonoscopy, the main difference between colonoscopy vs cologuard.
Why Have a Colonoscopy
Deciding between a colonoscopy vs Cologuard can be a tough decision, but ultimately, a colonoscopy is the best screening test and can prevent cancer and cancer deaths (53% reduction in colorectal cancer death) with the ability to remove polyps. If a Cologuard test is performed instead of a colonoscopy and comes back abnormal, you will have to have a colonoscopy to investigate the cause of it and remove polyps; if your Cologuard test comes back clear, there is a chance you could develop colon cancer or have it and not know it. You can save money and time by skipping the Cologuard test. Colonoscopies can save your life. If you have concerns about getting a colonoscopy or doing the bowel prep, it’s important to speak to your doctor. They can help work with you to ease your mind and make the procedure as comfortable as possible for you. Dr. Rosenfeld reserves the Cologuard test primarily for those patients who do not want a colonoscopy but will get one if a Cologuard test is positive.