Dr. Kara Vande Walle knows it’s a test few people want to talk about. However, a colonoscopy offers the only way to both screen for and remove colon polyps. That sets colonoscopy apart from other types of diagnostics that screen for colorectal cancer.
“Colonoscopy remains the gold standard for diagnosing colorectal cancer,” says Dr. Vande Walle, a General Surgeon who performs colonoscopies with ThedaCare. “It’s a very effective tool for detecting and preventing cancer. It also allows us to remove polyps at the same time as we do the procedure.”
Polyps and Colorectal Cancer
A colon polyp is a small clump of cells that forms on the lining of the colon. Most colon polyps are harmless. However, some polyps, over time, can turn into colorectal cancer. The disease can be deadly if found in its later stages.
“Most people with colon polyps do not have symptoms, which is why colonoscopies are so important,” Dr. Vande Walle says.
With March observed as Colorectal Cancer Awareness Month, Dr. Vande Walle says it’s a good time to review risk factors, symptoms and screening methods.
Risk Factors
Anyone can develop colon polyps. Risk increases as you age, with polyps most common in those 50 and older.
Other risk factors for polyps and colorectal cancer include:
- Family history of the disease
- Obesity
- Diets high in red or processed meats
- Diets low in fiber, fruits and vegetables
- Heavy alcohol use
- Genetic syndromes such as Lynch syndrome
Symptoms
“One of the best things you can do for your health is to watch for changes and talk to your health care provider promptly if you have a symptom that concerns you,” Dr. Vande Walle says. “Your health care provider can help determine if it’s something concerning and you need further monitoring or treatment, or if only reassurance is needed.”
Watch for these symptoms:
- Changes in bowel habits lasting longer than a week. A large colon polyp or colon cancer can cause long-term diarrhea or constipation. Other conditions also can cause a change in bowel habits.
- Changes in stool color. Blood can show up in streaks or make stool black. Medication or food also can cause a change. However, it’s good to mention any changes to your physician or provider.
- Mucus in stool. Stool often contains a small amount of mucus, but if you notice an increased amount, mention it to your physician or provider. Mucus by itself is not a reason to worry, but your doctor will want to know if it is present with other symptoms.
- Anemia. Bleeding from polyps can happen slowly over time, without visible blood in the stool. Chronic bleeding may lead to iron-deficiency anemia, which can cause tiredness and shortness of breath.
- Pain. A large colon polyp can block part of the bowel, leading to cramping and belly pain.
It’s also important to recognize that many people with colon polyps or early-stage colorectal cancer do not have symptoms. This makes screening critical.
Screening Guidelines
In 2021, national health organizations began recommending regular colorectal cancer screenings starting at age 45 for people at normal risk. That’s five years earlier than the previous recommended age of 50. An increased incidence of late-stage colon cancer in younger people led to the guideline change.
The overall rate of people diagnosed with colon or rectal cancer has dropped since the mid-1980s, according to the American Cancer Society (ACS). That’s thanks to more people getting screened and changing their lifestyle-related risk factors.
For younger adults, the trend isn’t as promising. In January 2026, the Journal of the American Medical Association shared a study that identified colorectal cancer as the leading cause of cancer deaths in people younger than 50.
“We are still working to understand what’s driving the uptick,” Dr. Vande Walle says. “Getting screened remains the most important step for early detection — when colorectal cancer is most treatable.”
Screening Types
The ACS outlines the following main colorectal cancer screening options:
- Visual tests
- Colonoscopy — every 10 years through age 75 if normal results
- CT colonography (virtual colonoscopy) — every 5 years
- Sigmoidoscopy — every 5 years
- Stool-based tests
- Highly sensitive fecal immunochemical test (FIT) — every year
- Highly sensitive guaiac-based fecal occult blood test (gFOBT) — every year
- Multi-targeted stool DNA test with fecal immunochemical — every 3 years
It’s important to note that if someone chooses a screening test other than a colonoscopy and the result is abnormal, they should get a colonoscopy soon after.
“We always encourage people to get screened, period,” Dr. Vande Walle says. “As you’re choosing, know that colonoscopy is the only screening tool that allows us to look at the entire colon and rectum and remove polyps. For a test most people only have to do every 10 years, it’s worth it.”
