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What if we had a way to prevent colon cancer? We do, according to Hassan Tariq, MD.

“Colonoscopy is the only screening test that can actually prevent colon cancer from developing,” says Dr. Tariq, gastroenterologist, UPMC Gastroenterology Associates of Central PA. “During the test, we find and remove small growths called polyps that can develop into cancer.”

Colonoscopy is the most accurate way to screen for colorectal cancer, but it’s not the only option.

In recent years, at-home stool DNA tests like Cologuard^® have become popular because they are simple to use. But are at-home tests as good as a colonoscopy?

“Colonoscopy is the gold standard test that has been proven to decrease colorectal cancer in our population,” Dr. Tariq says. “But the best colon cancer test is the one you’re willing to take.”

Here’s what you should know about colorectal cancer screening.

What Happens During a Colonoscopy?

Colonoscopy is the most accurate screening test for colorectal cancer. For the test to be successful, your doctor will need to have a clear view of your large intestine. That means you need to empty all stool from your colon before the test.

To do that, your doctor will prescribe a liquid-only diet for a day or two before your colonoscopy. You’ll add a laxative regimen in the hours before the test to ensure your bowel is clean.

“We try to tailor the bowel prep so that the patient is willing to take it,” Dr. Tariq says. “No one likes that part, but we try to make it as pleasant as possible, and it doesn’t last long.”

Typically, you’ll go to an outpatient clinic or hospital suite for your colonoscopy. You’ll likely go home after just a few hours, including time for the test and recovery.

After you receive IV sedation, your doctor will gently insert a special scope into your anus. This scope is a long, flexible tube with a small video camera and a light on the end. Your doctor will move the scope through your rectum and colon, studying every inch in detail.

If your doctor sees something suspicious, such as a polyp, they’ll thread instruments through the scope and clip the growth off your intestinal wall. You won’t feel or remember anything about the procedure.

Dr. Tariq says people are often surprised at how easy the test is.

“They’ll count backwards for the anesthesiologist, and the next thing they know, they’re in the post-op area waking up,” he says.

You’ll receive a report that notes if your doctor found any polyps. If so, the report will tell you how many polyps and whether they are likely to become cancerous over time.

The report will also tell you when you should receive your next colonoscopy. If the results are normal, you may not need another colonoscopy for 10 years.

How Do At-Home Tests Work?

At-home stool DNA tests screen your stool sample for blood. They also check for abnormal DNA in the sample. Precancerous and cancerous cells commonly shed abnormal DNA fragments.

You need a prescription to order an at-home stool DNA test. The company will ship the test collection kit to your home. You’ll collect your stool sample in the privacy of your bathroom, then ship it back to the company.

Dr. Tariq says many of his patients ask him about at-home stool tests.

“It is a convenient, noninvasive test that checks for early signs of colon cancer,” he explains. “At-home tests are a good option for average-risk patients who either aren’t ready to undergo a colonoscopy or are high risk for sedation.”

But at-home tests aren’t perfect, he cautions, and false negatives sometimes occur.

If your at-home stool test results are normal, you should repeat the test in three years.

What Are the Benefits of Colonoscopy Over Stool-Based Tests?

Although taking a stool DNA test at home is easy and private, it is only for people who do not have an increased risk of colorectal cancer.

For example, people with any symptoms of colorectal cancer should get a colonoscopy and not an at-home test. These symptoms include:

• Anemia.
• Bleeding from the anus.
• Blood in the stool.
• Persistent abdominal pain.
• Unexplained weight loss.

Dr. Tariq stresses that you’ll still need a colonoscopy if an at-home test shows abnormal results. If you do need a colonoscopy, your insurance company may consider it to be a diagnostic test rather than a screening test.

Insurance companies often cover screening colonoscopies at 100%. Coverage for diagnostic colonoscopies may be significantly lower.

“Patients sometimes have to pay several thousand dollars when it would have been 100% covered if they had undergone a screening colonoscopy instead,” Dr. Tariq says.

Dr. Tariq recommends having a candid conversation with your doctor to understand personal colorectal cancer risk factors. That way, people can make an informed decision about colorectal cancer screening.

Who Is at Risk of Colon Cancer?

Doctors diagnose about 150,000 cases of colorectal cancer per year in the United States, according to the American Cancer Society (ACS). Colorectal cancer is the third-leading cause of cancer deaths in U.S. men and the fourth leading cause of cancer deaths in women. That number rises to the second most common cause of cancer deaths for men and women combined.

“In Pennsylvania, we diagnose about 6,500 new cases of colorectal cancer every year,” Dr. Tariq says. “It’s important that you talk to your doctor and make a screening plan for yourself.”

Nationally, new cases of colorectal cancer in older adults have decreased by about 1% per year since 2012. That’s due to more people getting colorectal cancer screening.

But doctors are diagnosing more people younger than age 50 with colorectal cancer than ever before. Diagnoses in people under 50 increased by 2.4% per year from 2012 to 2021, the ACS says.

In response, the ACS lowered the recommended age to start regular colorectal cancer screening to age 45. Previously, people at average risk could safely wait until age 50 to start screening.

People can have an increased risk of colorectal cancer if they have certain lifestyle factors, including:

• A diet heavy on meat and processed foods.
• Heavy alcohol or tobacco use.
• Obesity.
• Type 2 diabetes.

Other risk factors for colorectal cancer include:

• Familial adenomatous polyposis (FAP).
• Family history of colorectal cancer, especially in your parents, siblings, or children.
• Inflammatory bowel disease, such as ulcerative colitis or Crohn’s disease.
• History of high-risk polyps.
• History of pelvic radiation for a previous cancer.
• Lynch syndrome, a genetic predisposition.

*Cologuard® is a trademark of Exact Sciences Corp.