Colon Cancer Screening: How to Prevent Colon Cancer

In the early stages of colon cancer – the fourth most common cancer in the US and the second leading cause of death from cancer – there are usually no obvious symptoms. And yet, if caught early, it is easily treatable.

Thanks to screening, colon cancer rates have steadily declined in people in their 50s and 60s, says Jeffrey Meyerhardt, chief clinical research officer at the Dana-Farber Cancer Institute in Boston and a professor at Harvard Medical School. At the same time, he says, colon cancer rates in people under 50 steadily increasing by almost 2 percent per year.

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Who should get a colonoscopy?

In response to this increase in younger people who American Cancer Society and the US Task Force on Preventive Services recommend colorectal cancer screening for people aged 45 and over without a family history. That’s five years earlier than previous recommendations.

But only 11 percent of people between the ages of 45 and 49 actually get this first colonoscopy, considered the gold standard of colorectal cancer screening in the United States CDC found.

The American Cancer Society says people list several reasons why they don’t get a colonoscopy:

• Lack of health insurance or transportation

• Inability to take time off work

• believe they do not need the test because they have no family history or symptoms

• Worry about the cost

• embarrassment

But people may not realize how many options there are.

Tests for colon cancer

Colonoscopy is a one-step screening test because the doctor performing the procedure can remove any detectable polyps right away.

The procedure is good for 10 years for average-risk people, says Hartford HealthCare gastroenterologist Cassidy Alexandre. But for people with a first-degree relative (like a parent or sibling) who had colon cancer, doctors recommend Start screening at 40 and repeat colonoscopy every five years.

Other screening options are considered two-step tests, because if the stool sample comes back positive for possible signs of colon cancer, the patient is sent for a colonoscopy, Alexandre says. While there are many alternatives to colonoscopy, doctors generally recommend two screening tools most commonly: the fecal immunochemical test (FIT) and the Stool DNA Test.

What is the FIT test?

The FIT looks for microscopic blood in the stool using an antibody that binds to a blood protein called hemoglobin, Alexandre explains. If you have hemoglobin in your stool, it means you also have blood in your stool, he says — which could be a sign of colon cancer.

Even if the test comes back negative, doctors recommend repeating it every year if they haven’t had a colonoscopy.

The FIT test has been shown to effectively detect colon cancer and fewer polyps, which are often precursors to colon cancer, Meyerhardt says. “It’s the least sensitive option,” he says, “but it’s still an option.”

What is the stool DNA test?

This test looks for changes in the cells’ DNA, as some DNA changes could indicate a risk of cancer or the presence of cancer. This test also looks for microscopic blood in the stool.

Cologuard is the only stool DNA test approved for colorectal cancer screening, says Alexandre. Patients with a negative test are recommended to repeat every three years.

It’s a good screening technique and a very sensitive test, Meyerhardt adds.

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Less frequent screening for colorectal cancer

Fecal Occult Blood Test (FOBT) has been used as a screening test in the past but has fallen out of favor with gastroenterologists due to its high rate of false positives, explains Alexandre.

Certain foods and medications must be avoided a few days before the test. Additionally, it also fails to detect some polyps and cancers — and if microscopic blood is detected, further testing is likely needed.

Flex sigmoidoscopy

With a flexible sigmoidoscopy, Doctors look at half of the colon. Patients do not need to go through the full colon cleansing preparation as an enema on the day of the test is usually sufficient.

However, the problem with this test is that the majority of people who have polyps or cancer will have them on their skin To the right side – and this test only examines the right side, says Alexandre.

What about virtual colonoscopies?

There is also one for patients who cannot tolerate or wish to avoid anesthesia, like President Barack Obama did during his administration Virtual Colonoscopy known as CT colonography.

During this procedure, the patient performs full bowel prep to clean out their colon and then drinks a barium liquid to help the doctor look inside. Air is introduced to inflate and dilate the colon to make polyps easier to see.

The CT scan allows the doctor to look inside the colon and rectum to look for polyps. This test was more popular 15 years ago than it is now, says Meyerhardt, because “a small polyp can’t be seen.”

Blood tests for colorectal cancer screening

There is a blood-based DNA test for an altered gene called SEPT9. This option is FDA-approved for adults age 50 and older with an average risk of colon cancer who have not completed colorectal cancer screening in the past.

However loud National Cancer Institutethere is no evidence that this test can reduce deaths from colorectal cancer.

“Blood-based tests of tumor DNA have developed into a very powerful tool in recent years,” says Meyerhardt. “However, there is still a lot to learn about how the results can be used for both cancer screening and the treatment of cancer patients.”

The FirstSight blood test is one of many tests in development, he says, and early data from the test shows promise for screening for colorectal cancer. “But the sensitivity for advanced adenomas, which can eventually become cancer, is low,” he concludes.

How to prevent colon cancer

Of course, one of the most effective ways to prevent death from colon cancer is to get screened regularly, says Meyerhardt.

This is especially important for black patients, whose rates of colon cancer are high the highest of any racial or ethnic group in the country. African Americans are about 20 percent more likely to get colon cancer — but they’re also more likely to get it at a younger age, receive late-stage diagnoses, and die from it than the general population, Alexandre says.

But there are other ways to lower your risk of contracting the disease in the first place, Alexandre says. These include the recommended 150 minutes of moderate exercise per week, maintaining a healthy weight, not smoking, limiting red and processed meat, and limiting alcohol consumption.

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