Colorectal cancer is common.
“Colorectal cancer is the third most common cancer in men and women in the United States,” says Dr. Nimeesh Shah, chief of the division of gastroenterology and hepatology at Santa Clara Valley Medical Center in San Jose, California.
It’s most commonly diagnosed in people over the age of 50, but “it’s estimated that 10.5% of new colorectal cancer cases occur in individuals less than 50 years old,” Shah says. What’s more, he notes that “the incidence of colorectal cancer in adults ages 40 to 49 has increased almost 15% in the past two decades.”
Screening can prevent or catch it early.
While colorectal cancer is common, there are a few screening methods that can help detect it early, when it’s in its most treatable phase.
Dr. Anita Gregory, medical director of the colorectal program at the Center for Cancer Prevention and Treatment at Providence St. Joseph Hospital in Orange County, California, says that across all types of cancer, “screening tests are designed to detect early, precancerous changes in the affected organ so that interventions can be implemented to prevent the development of cancer.”
In the colon specifically, “these changes are growths called polyps, and detection and removal of polyps can prevent colon cancer.”
There are two main ways in which you can be screened for colon cancer: stool testing and visualization tests.
With stool testing, you collect a stool sample, which is “often done from the comfort of home,” says Dr. James Ellzy, a practicing family physician in Washington, D.C., and a member of the American Academy of Family Physicians board of directors. The sample is then sent to a lab for testing.
The laboratory will look for signs of cancer using two approaches, Shah says. These include:
— A fecal immunochemical test, also called a FIT test, which detects blood in the stool.
— A FIT-fecal DNA test, which detects DNA biomarkers for cancer in cells shed from the lining of the colon and rectum into stool.
“Both FIT and FIT-fecal DNA stool tests aim to find early stage curable cancer,” Shah says.
If the test is positive and cancer is detected, your doctor will follow up with a colonoscopy for further evaluation.
“Diagnoses of colon cancer have to be validated by pathology, which will entail taking and examining a biopsy” of the polyp once it’s found on a colonoscopy, says Dr. Idan Levy, a gastroenterologist and head of the innovative endoscopy unit at Sheba Medical Center in Israel.
The upside to stool testing is that it’s less invasive and can usually be collected at home. “However, these tests will need to be performed more frequently,” Ellzy says.
Shah notes that this type of screening test should be conducted “every three years as long as” you get a negative result. But false negatives can sometimes be a problem with this type of testing. “Certain pre-cancerous colon polyps can be missed when using stool-based screening.”
Stool testing has been shown to be 92% accurate, Gregory says, but “colonoscopy remains the gold standard for colon polyp and cancer detection.”
“Direct visualization tests like colonoscopies (which provide a view of the entire colon) and flexible sigmoidoscopies (which look at only a portion of the colon) are performed in a clinic setting and use a thin, flexible tube with a light and camera attached. This allows the physician to check for problems in the colon,” Ellzy says.
A big benefit of this more invasive procedure is that your doctor can remove polyps and potential cancers during the exam, without having to bring you back for more testing or another procedure.
What’s more, “a colonoscopy is the only form of colorectal cancer screening that can potentially prevent an individual from getting colorectal cancer,” Shah says. This is because these tests can spot polyps before they might become problematic or cancerous. Your doctor can remove any concerning polyps at the time the screening test is performed.
“Colonoscopies are typically done every five to 10 years, depending on the patient’s age, risk factors and family history,” Ellzy says.
Colonoscopy is the gold standard.
To be honest, colonoscopies aren’t a lot of fun. They require you to follow a strict diet in the day or two beforehand to prepare the colon, and they can be uncomfortable. They’re invasive, and for some, they can cause anxiety, Levy says. However, that shouldn’t hold you back from getting this important screening. “With the advancement of technology and the types of sedation now available, it’s now comfortable as ever.”
Despite their being somewhat intimidating, colonoscopies remain the best defense against colorectal cancer.
“Colonoscopy is the only screening option that can allow the complete examination of the entire colon and affords the opportunity to remove precancerous lesions during the same examination,” says Dr. Adeyinka Laiyemo, associate professor of medicine in the division of gastroenterology at Howard University College of Medicine in Washington, D.C. “This gives it a major advantage over the other screening options.”
Other colon cancer screening options
In addition to visualization tests and stool screenings, sometimes another method of screening called computed tomography colonography, or CT colonography, is used, Ellzy says. “Sometimes called a ‘virtual colonoscopy,’ this test is noninvasive and works like an X-ray, using a low dose of radiation to see the inside of the colon.”
Virtual colonoscopy is typically recommended to be undertaken every five years, Laiyemo says.
Another modality is a capsule colonoscopy. Shah says this less-frequently-used screening test involves ingesting a small camera that takes pictures of the colon. He adds that capsule colonoscopy and virtual colonoscopy “are not as good as a colonoscopy or stool-based test at finding cancer or pre-cancerous lesions. Abnormal findings on any of these other tests also require a follow-up colonoscopy for further evaluation.”
Video capsule colonoscopy is usually recommended every five years, Laiyemo says.
The benefits and risks of harm vary for the different tests, so it’s important to discuss your options with your family physician, Ellzy adds.
When should I start colon cancer screening?
“The American Academy of Family Physicians recommends screening for colorectal cancer with stool sample or colonoscopy starting at age 50 and continuing until age 75,” Ellzy says. “Individuals aged 76 to 85 should discuss the potential benefits and harms of screening.”
Other guideline-creating organizations have slightly different recommendations. Given the recent increase in colorectal cancers in people under age 50, the U.S. Preventive Services Task Force, the American Cancer Society and the American College of Gastroenterology all now recommend starting screening for colorectal cancer at age 45, rather than waiting until age 50, Shah says.
Dr. Rachel Issaka, a gastroenterologist at Seattle Cancer Care Alliance and assistant professor at the Fred Hutchinson Cancer Research Center and the University of Washington, adds that “if you’re 45 years or older and have never been screened for colorectal cancer, create a plan today. Screening could save your life.”
Ellzy notes that the AAFP is currently reviewing scientific evidence and will be updating its recommendations in the near future.
How often should I get screened?
Most people at average risk of developing colorectal cancer are advised to undergo a colonoscopy every 10 years. The term “average risk” is used instead of “low risk” because “anybody with a colon has a risk of colon cancer,” Laiyemo says.
But this advice can vary, says Issaka. “How often screening should be repeated depends on what’s found during the initial screening test.”
For example, if you have a family history of colorectal cancer or symptoms that could indicate colorectal cancer, which may include blood in the stool, abnormal weight loss, unexplained abdominal pain or changes in stool such as the development of constipation, you should discuss your care with a health care provider.
In addition, Gregory notes that a personal or family history of inflammatory bowel disease and “certain genetic syndromes warrant earlier and more frequent screening.”
Which test is best?
The determination of which test is best is a highly individual one, Ellzy says. “It’s important for every person to talk with their family physician about which screening method is right for them. Screening recommendations may vary based on a person’s risk factors and personal and family health history.”
Levy notes that additional factors may also come into play. “The best method will depend on a patient’s individual set of circumstances and preferences, the skills of the person carrying out the colonoscopy, the availability of different options in the specific health care system and the costs for the health care system.”
For example, Levy says that “for a patient with a severe heart or lung disease, the virtual colonoscopy might be the best option. In a case where the patient has a fear of colonoscopies but still needs or wants to be screened and would be willing to perform a colonoscopy should the screening have a positive result, the stool test may be the best option.”
For Issaka, the answer is simple: “The best colorectal cancer screening test is the one that gets done and done well.”
Laiyemo agrees. If screening colonoscopy can’t be performed for one reason or another, “the best screening test can be considered as the test that’s acceptable to the patient, gets done well and the process of screening gets completed with follow-up of abnormal findings.”
Learn your family history.
When it comes to making a plan for colorectal cancer screening, Laiyemo recommends starting by talking with “your family members about their health and whether they have been diagnosed with cancer or large precancerous polyps in their colon or rectum.”
It might not be the kind of chat you want to have over dinner, but this is important information that can help determine when you should begin colon cancer screening. “For example, if your father was diagnosed with colon cancer when he was 43 years old, you’ll have to be screened with colonoscopy when you turn 33 years of age, (or 10 years earlier than the family member’s age at diagnosis) rather than at 45 years of age that’s recommended for average risk persons.”
With that information in hand, talk to your health care provider during your annual checkup to make a plan.
Screening saves lives.
Colorectal cancer can be dangerous, and symptoms often don’t show up until it’s well advanced. But if detected early, before the disease has progressed, colon cancer can potentially be cured, Shah says. “As such, it’s important to be screened for colon cancer rather than to wait for symptoms to start, in which case the cancer may potentially be late-stage with an associated increased morbidity and mortality.”
“The bottom line,” says Anthony Senagore, a colorectal surgeon based in Michigan, is that “any screening process is better than none.”
What to know about colorectal cancer screening tests:
— Stool testing is less invasive.
— Colonoscopy is the gold standard.
— Virtual colonoscopy and video capsule colonoscopy may be a good option for some people.
— Talk with your doctor about when to start screening; most people should start at age 45.
— Keep up with your routine screenings as recommended by your doctor and guideline agencies for the modality you’re using.
— The best test is the one you’ll do regularly.
— Screening saves lives.
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