In the early stages of colon cancer — on the fourth most common cancer in the US and the second leading cause of cancer death – usually has no obvious symptoms. Still, if caught early, that is highly treatable.
Thanks to screening, the incidence of colon cancer has declined steadily among people in their 50s and 60s, says Jeffrey Meyerhardt, chief clinical investigator at the Dana-Farber Cancer Institute in Boston and a professor at Harvard Medical School. At the same time, he says, colon cancer rates among people under 50 years of age steadily increasing by nearly 2 percent per year.
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Who should get a colonoscopy?
In response to this increase in younger people, American Cancer Society and on US Preventive Services Task Force recommend colon cancer screening for those without a family history beginning at age 45. This is five years earlier than previous recommendations.
Still only 11 percent of people aged 45 to 49 actually receive this first colonoscopy, considered the gold standard of colon cancer screening tests in the US. CDC found.
The American Cancer Society says that people list several reasons for not getting a colonoscopy:
- lack of health insurance or transportation
- inability to take leave from work
- believe they do not need the test because they have no family history or symptoms
- cost concern
- disturbance
But people may not realize how many options there are.
Tests for colon cancer
A colonoscopy is a one-step screening test because the doctor performing the procedure can immediately remove any detectable polyps.
The procedure is good for 10 years for those at average risk, says Hartford HealthCare gastroenterologist Cassidy Alexander. But for people with a first-degree relative (such as a parent or sibling) who has had colon cancer, doctors I recommend starting screening at 40 and repeating the colonoscopy every five years.
Other screening options are considered two-step tests, because if the stool sample comes back positive for potential signs of colon cancer, the patient is sent for a colonoscopy, Alexander says. Although there are many alternatives to colonoscopy available, doctors most often recommend two screening tools: fecal immunochemical test (FIT) and on Stool DNA test.
What is the FIT test?
FIT checks for microscopic blood in the stool by using an antibody that binds to a blood protein called hemoglobin, Alexander explains. If you have hemoglobin in your stool, that means you also have blood in your stool, he says—which could be a sign of colorectal cancer.
Even if the test comes back negative, doctors recommend repeating it every year if you haven’t had a colonoscopy.
The FIT test has been shown to effectively detect colorectal 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 a stool DNA test?
This test looks for changes in the cells’ DNA, as some changes in DNA can signal cancer risk or the presence of cancer. This test also looks for microscopic blood in the stool.
Cologuard is the only stool DNA test approved for colon cancer screening, Alexander says. Patients with a negative test are advised to repeat it every three years.
It’s a good screening technique and a very sensitive test, Meyerhardt adds.
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Less common colon cancer screenings
Fecal occult blood test (FOBT) has been used as a screening test in the past, but has fallen out of favor with gastroenterologists because of the high number of false positives, Alexander explains.
Certain foods and medications should be avoided for a few days before the test. In addition, it also fails to detect some polyps and cancers – and if microscopic blood is found, more tests are likely to be needed.
Flex sigmoidoscopy
S flexible sigmoidoscopy, doctors look at half of the colon. Patients do not need to go through the full preparation for bowel cleansing, as an enema on the day of the test is usually sufficient.
The problem with this test, however, is that most people who have polyps or cancer will have them on exactly side—and this test only examines the right side, Alexander says.
What about virtual colonoscopies?
For patients who cannot tolerate anesthesia or want to avoid it, such as President Barack Obama while in office, there are also virtual colonoscopy known as CT colonography.
During this procedure, the patient performs a full bowel preparation to clean out their colon, then drinks barium fluid to help the doctor see inside. Air is introduced to inflate the colon and expand it to make the polyps more visible.
A CT scan allows the doctor to see the inside of the colon and rectum and look for polyps. This test was more popular 15 years ago than it is now, Meyerhard says, because “a small polyp won’t be seen.”
Colon cancer screening blood tests
There is a blood DNA test for an altered gene called SEPT9. This option is FDA-approved for adults age 50 and older at average risk of colon cancer who have a history of not completing colon cancer screening tests.
However, according to National Cancer Institutethere is no evidence that this test can reduce deaths from colorectal cancer.
“Blood-based tumor DNA testing has become a very powerful tool in the last few years,” says Meyerhardt. “However, there is still much to learn about how to use the results to both screen for cancer and treat cancer patients.”
The FirstSight blood test is one of several tests being developed, he says, and initial data from this test are promising for colorectal cancer screening. “But the sensitivity for advanced adenomas, those that may eventually turn into cancer, is low,” he concludes.
How to protect yourself from colon cancer
One of the most effective ways to prevent death from colon cancer is, of course, regular screening, Meyerhardt says.
This is especially important for black patients, whose rates of colon cancer are the highest of any racial or ethnic group in the state. African-Americans are about 20 percent more likely to get colorectal cancer, but are also more likely to get it at a younger age, be diagnosed at a late stage, and die from it than the general population. says Alexander.
But there are other ways to reduce your risk of contracting the disease in the first place, Alexander says. These include the recommended 150 minutes a week of moderate exercise, maintaining a healthy body weight, not smoking, limiting red and processed meats and limiting alcohol consumption.
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