In the early stages of colon cancer — the fourth most common cancer in the United States and the second leading cause of death from cancer – there are usually no obvious symptoms. And yet, if caught early, it is highly treatable.
Thanks to screenings, colon cancer rates have steadily declined among people in their 50s and 60s, says Jeffrey Meyerhardt, director of clinical research at the Dana-Farber Cancer Institute in Boston and professor at Harvard Medical School. At the same time, he says, colon cancer rates among those under 50 steadily increased by almost 2% per year.
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Who should have a colonoscopy?
In response to this increase in the number of young people, the American Cancer Society and the US Task Force on Preventive Services recommend colon cancer screening for people without a family history starting at age 45. This is five years earlier than previous recommendations.
Yet only 11 percent people between the ages of 45 and 49 actually receive this first colonoscopy, considered the gold standard for colon cancer screening tests in the United States. CDC find.
THE American Cancer Society says people list several reasons for not having a colonoscopy:
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lack of health insurance or transportation
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inability to miss work
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believing they don’t need the test because they don’t have a family history or symptoms
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cost concern
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embarrassment
But people may not realize how many options there are.
Colon cancer tests
Colonoscopies are 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 people at average risk, says Cassidy Alexandre, a gastroenterologist at Hartford HealthCare. But for people with a first-degree relative (such as a parent or sibling) who has had colon cancer, doctors recommend begin screening at age 40 and repeat 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 then sent for a colonoscopy, Alexandre says. Although there are many alternatives to colonoscopy, doctors generally recommend two screening tools most often: the fecal immunochemical test (FIT) and the stool DNA test.
What is the FIT test?
FIT checks the stool for microscopic blood, using an antibody that binds to a blood protein called hemoglobin, explains Alexandre. 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 is negative, doctors recommend repeating it every year if they have not had a colonoscopy.
The FIT test has been shown to be effective in detecting colorectal cancers, and less polyps which are often precursors to colon cancer, says Meyerhardt. “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 DNA of cells, as certain changes in DNA could signal 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 colon cancer screening, says Alexandre. Patients who test negative are advised to repeat every three years.
It’s a good screening technique and a very sensitive test, adds Meyerhardt.
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Less Common Colon Cancer Screenings
Fecal occult blood test (FOBT) had been used as a screening test in the past but fell out of favor with gastroenterologists due to its high number of false positives, says Alexandre.
Certain foods and medications should be avoided for several days before the test. Additionally, it also fails to detect certain polyps and cancers – and if microscopic blood is detected, further testing will likely be required.
Flex sigmoidoscopy
With a flexible sigmoidoscopy, doctors examine half of the colon. Patients do not have 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 the majority of people who have polyps or cancer will have them on their LAW side – and this test only looks at the right side, says Alexander.
What about virtual colonoscopies?
For patients who cannot tolerate anesthesia or want to avoid it, like President Barack Obama when he was in office, there is also a virtual colonoscopy known as CT colonography.
During this procedure, the patient performs full bowel prep to clean out their colon, then drinks barium fluid to help the doctor see inside. Air is inserted to inflate the colon and expand it to make the polyps more visible.
The CT scan allows the doctor to see inside the colon and rectum and look for polyps. This test was more popular 15 years ago than it is now, says Meyerhardt, because “a small polyp won’t be seen.”
Blood tests for colon cancer screening
There is a blood-based DNA test for an altered gene called SEPT9. This option is FDA-approved for adults 50 and older at average risk for colon cancer who have a history of not having colon cancer screening tests.
However, according to the National Cancer Institutethere is no evidence that this test can reduce the number of deaths from colorectal cancer.
“Tumor DNA blood tests have become a very powerful tool in recent years,” says Meyerhardt. “However, there is still much to learn about how to use the results both for cancer screening and for the treatment of cancer patients.”
The FirstSight blood test is one of several tests in development, he says, and early data from this test show promise for colorectal cancer screening. “But the susceptibility to advanced adenomas, those that can eventually become cancer, is low,” he concludes.
How to prevent colon cancer
One of the most effective ways to prevent death from colon cancer is, of course, to get screened regularly, Meyerhardt says.
This is especially important for black patients, whose colon cancer rates are highest of any racial or ethnic group in the country. African Americans are about 20% more likely to get colorectal cancer – but they’re also more likely to get it at a younger age, be diagnosed at an advanced stage, and die of it than the general population , said Alexander.
But there are other ways to lower your risk of getting the disease in the first place, says Alexander. These include getting the recommended 150 minutes per week of moderate exercise, maintaining a healthy body weight, not smoking, limiting red and processed meats, and limiting alcohol intake.
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