Key Takeaways (TL;DR):
Due to a sharp rise in cases among younger adults, the recommended age to begin colorectal cancer (CRC) screenings has been lowered from 50 to 45.
CRC is the second leading cause of cancer death in the U.S., often showing no symptoms in early stages when it is most treatable.
Colonoscopy remains the most accurate method of screening because it’s the only procedure that can both detect and remove precancerous polyps during the same appointment.
Non-invasive tests like Cologuard, FIT, and the new Shield blood test offer patients increased convenience, but are less effective at detecting polyps. If test results are positive, a follow-up colonoscopy is required.
While genetics and race play a role in risk, individuals can proactively lower their risk of CRC through regular exercise, avoiding tobacco & alcohol, and—most importantly—adhering to a consistent screening schedule.
Colon cancer isn’t something most people like to talk about— but it’s something anyone over 45 should be concerned about. Because it’s one of the fastest growing cancers in people under the age of 50, the medical community has lowered the recommended age for colorectal cancer screening to 45.
Also known as bowel cancer, colorectal cancer starts in the colon or rectum and often has no symptoms in its early stages, when it’s easiest to treat. Colorectal cancer (CRC) is the third most common cancer in the world, and the second leading cause of death from cancer in the United States.
Getting screened can save your life, and today you’ve got more choices than ever for how to do that.
Facts about colorectal cancer
Every year, colorectal cancer claims more than 50,000 American lives, even though early detection and treatment could prevent most of those deaths.
Colorectal cancer often begins as a growth called a polyp inside the colon or rectum. Screening is effective for identifying precancerous polyps and early-stage cancer before symptoms appear. Early diagnosis and treatment can greatly reduce the risk of death from CRC.
In most cases, regular CRC screenings are recommended for people between the ages of 45 to 75. Individuals who are at increased risk for CRC due to family history or other factors may begin screening earlier and more often.
What are the risk factors for colorectal cancer?
There are a number of risk factors for colorectal cancer, including many that are beyond an individual’s control, including:
- Race
- Family history of cancer
- Personal history of cancer, and
- Age
- Obesity
What can protect you from colon cancer?
There are also a few protective factors that individuals can control, which will decrease their risk of getting colorectal cancer.
Things an individual can do to help prevent colon cancer include:
- Exercise/physical activity
- Avoiding alcohol and cigarettes
- Taking aspirin
- Having polyps removed
But early detection through screening is the most powerful tool people have for protecting themselves from CRC.
Colorectal cancer screening options
Here are some screening options that can check for colon and rectal polyps or cancer:
1. Colonoscopy
The most accurate screening procedure, and probably the most familiar, is a colonoscopy. During this procedure, a gastroenterologist uses a flexible tube with a tiny video camera to view the interior of the patient’s colon. Patients are sedated during the procedure to minimize discomfort.
A colonoscopy is effective at diagnosing cancer, and can also help prevent cancer because any polyps found will be removed during the procedure.
Even so, many people fear and even avoid colonoscopies.
Why do people avoid colonoscopies?
One of the most common reasons for avoidance is that a colonoscopy is an invasive procedure requiring significant preparation by the patient in advance of the procedure.
To prepare for a colonoscopy, patients must eat a low fiber diet for 5 days. Plus, the day before, they need to fast and drink a liquid laxative to clear the colon, which makes it easier for the doctor to view the health of the colon during the procedure.
Because they will be sedated during the colonoscopy, patients must also miss a day of work, and will need to plan ahead and arrange for a driver, which is often a friend or family member. The driver must stay in the waiting room during their appointment, then drive the person home afterwards. This requires the patient to ask for help, plus coordinating several peoples’ schedules, to accommodate the procedure time.
Patients may also fear the results, although less than 1% of colonoscopies result in a cancer diagnosis. A colonoscopy detects 95% of precancerous polyps, which can be removed during the procedure. So getting screened is the key to maintaining good health.
How often is a colonoscopy needed?
Fortunately, for patients at average risk, a colonoscopy is only recommended once every 10 years if no polyps are found. For patients who have polyps, the next colonoscopy will be recommended in 1-5 years, depending on the number and size of the polyps removed.
Why colonoscopy is the gold standard for colorectal cancer screening
Because it’s the most accurate method of screening, and the only one which removes polyps, colonoscopy is always the preferred screening method for high-risk patients.
Anyone who has a positive test result from another screening method (Shield, Cologuard, or FIT test) will also need a colonoscopy in order to receive a definitive diagnosis and polyp removal.
Colonoscopies are performed by WWMG gastroenterologists at our certified and accredited Endoscopy Center.
2. Cologuard
Another at-home screening option is Cologuard, which offers a test kit by prescription. Patients collect a stool sample, then mail the kit back to the lab for testing. It does not require fasting.
The Cologuard test will identify blood or cancerous DNA in the sample, detecting 92% of colon cancers, but it is less accurate for detecting polyps, and has a relatively high false positive rate. As with other noninvasive tests, a positive Cologuard result will require a follow-up colonoscopy for definitive diagnosis.
If the test is negative, Cologuard only needs to be repeated every 3 years.
3. FIT test
FIT (also called an immunochemical fecal occult blood test or iFOBT), is a convenient, noninvasive screening that simply requires the patient to collect a stool sample. It does not require fasting.
FIT may be performed at home without a prescription, but you should still talk to your health care provider first to determine if it is the best test for you. FIT is only recommended for individuals who are not at elevated risk for CRC.
How does it work? Passing stool can damage blood vessels on the surface of polyps or cancerous growths, and when that happens, tiny amounts of blood are released. Although this blood is not visible to the naked eye, FIT (fecal immunochemical testing) can detect it.
While Cologuard tests for blood and DNA markers, FIT tests only for blood. FIT is not very good at detecting polyps, so it must be performed every year to be as effective as a colonoscopy.
Because there are other potential causes for blood in the stool, FIT produces more false positives than a colonoscopy, and a positive FIT result will require a follow-up colonoscopy for a definitive diagnosis.
4. Shield Blood Test
Shield is a new proprietary blood test by Guardant that was approved by the FDA in 2024. Medicare covers it, but many insurance companies have not yet added coverage for this test.
How does it work? As cancerous tumors grow, they release DNA into the bloodstream that can be detected by the Shield blood test. Although a simple blood draw is more convenient than a colonoscopy, Shield is not as effective in detecting early-stage cancer or polyps. Shield detects 65% of Stage I colorectal cancers and only about 13% of precancerous lesions.
At WWMG, the Shield blood test is available only at Everett Family Medicine to:
- Patients with Medicare, Medicare Advantage, or TriCare
- Patients with no family history of colon cancer
- Patients with no history of polyps
Shield is intended for patients who are at least 45 years of age, show no symptoms, and are at average risk for colon cancer. Patients with a positive Shield result will require a colonoscopy for a definitive diagnosis.
There is no widespread protocol (yet) for how frequent patients should receive Shield testing, so eligible patients must talk to their healthcare provider to determine the appropriate screening schedule.
Which screening method is right for you?
Only about 60% of Americans are up to date with colorectal cancer screening, which means that people are dying from a preventable cancer. The most effective cancer screening is the one that gets performed, so no matter which procedure you use, it’s important to get checked.
Please note, the availability of the Cologuard, FIT, and Shield screening tests may vary by which WWMG Family Medicine location you visit for your appointment. All tests may not be available at all locations. Colonoscopies are performed at WWMG’s outpatient Endoscopy Center.
If you are 45 or older and are:
- due for a colorectal cancer screening
- are not sure whether you’re due for a screening or
- would like to discuss the most appropriate screening method for you,
request an appointment with your WWMG primary care provider.
If you’ve had your screening and need to schedule a colonoscopy, call our Gastroenterology department at 425-259-3122 or request an appointment online.
We’re here to help you stay healthy and maintain a positive quality of life for many years to come.