Everyday Care

Colorectal cancer (CRC) remains one of the most common—and deadliest—cancers in the United States. According to the American Cancer Society, it is the third-leading cause of cancer-related deaths in men and the fourth in women. When combined, it ranks second overall. Each year, roughly 150,000 Americans are diagnosed, and more than 50,000 lose their lives.

There is some good news. From 2012 to 2021, overall CRC rates declined. But here’s the catch: that decline has largely been in older adults. In people under 50, rates are rising—and CRC has now become the leading cause of cancer-related death in this age group in the U.S.

That shift prompted major medical organizations—including the American College of Gastroenterology, American Cancer Society, and the U.S. Preventive Services Task Force—to lower the recommended starting age for average-risk screening from 50 to 45.

Why Screening Matters

Most colorectal cancers begin as polyps—small growths in the colon that usually cause no symptoms. That’s the key point: you can feel perfectly fine and still have a precancerous lesion.

Screening changes the game. When polyps are found and removed, cancer can often be prevented altogether. Multiple randomized controlled trials show screening reduces colorectal cancer incidence by 22% to 64%. A meta-analysis of seven major trials demonstrated a pooled 20% reduction.

In short: screening saves lives.

What Makes a Great Screening Test?

An ideal screening test is safe, affordable, simple, and highly accurate (measured by terms such as sensitivity and specificity). It should detect disease before symptoms develop, reduce mortality, and minimize false positives.

A multitude of colorectal cancer screening tests exist—each with strengths and tradeoffs.

Colonoscopy: The Gold Standard

Colonoscopy remains the most comprehensive screening tool. It detects and removes polyps in a single procedure, with greater than 90% sensitivity and specificity for colorectal cancer and advanced adenomas.

For average-risk individuals with a normal exam, screening is repeated only every 10 years.

The downsides? It’s invasive. It requires bowel preparation, sedation, time off work, and carries small, but real, risks such as bleeding or perforation. Still, it remains the most powerful preventive tool we have.

Flexible Sigmoidoscopy: A Limited but Proven Option

Think of flexible sigmoidoscopy as colonoscopy “lite.” It examines only the lower portion of the colon and is typically repeated every 5–10 years.

While less sensitive than full colonoscopy, randomized trials show it reduces colorectal cancer mortality by 22%. It’s a reasonable alternative, though used less commonly today.

Stool-Based Testing: Convenient and Growing in Popularity

Stool-based tests have seen rapid growth. Between 2017 and 2023, multi-target stool DNA testing rose from 2.4% to 20% utilization.

FIT (Fecal Immunochemical Test)

FIT detects hidden blood in the stool using antibodies specific to human hemoglobin. It’s simple, noninvasive, requires no dietary restrictions, and is done annually.

It performs well for detecting cancer, though it is less sensitive for advanced precancerous polyps (and does not reliably detect serrated lesions, a type of premalignant colorectal polyp).

Multi-Target Stool DNA and RNA Tests

Commercially available DNA and RNA stool tests build on FIT by detecting both genetic and epigenetic alterations in DNA and RNA biomarkers shed from colorectal lesions into stool respectively. These tests have sensitivities in the 90% range for cancer and are nearly twice as sensitive as FIT for advanced adenomas. They are performed every three years.

The tradeoff? Lower specificity, more false positives, higher cost, more follow-up colonoscopies, and uncertainty about surveillance after a positive test with a negative colonoscopy.

Blood-Based Screening: The New Kid on the Block

Blood-based cell-free DNA testing analyzes tumor DNA fragments circulating in the bloodstream.

It’s appealing—just a simple blood draw. While sensitivity for colorectal cancer is promising, detection rates for advanced precancerous lesions remain low (in the teens). Modeling studies suggest it is currently less effective than stool-based strategies for primary screening.

It’s an exciting development—but gaps remain regarding real-world performance, adherence patterns, and long-term outcomes.

CT Colonography: The Virtual Colonoscopy

CT colonography uses advanced imaging to create 2D and 3D views of the colon. It’s performed every five years and detects CRC and larger polyps well.

However, it still requires bowel preparation. It exposes patients to low-dose radiation, and incidental findings outside the colon are common—often leading to additional testing. And if a polyp is found? You’ll still need a colonoscopy.

The Bigger Problem: We’re Not Screening Enough

Despite all these options, only about 62–67% of eligible Americans are up to date with screening, well short of the 80% goal set by the National Colorectal Cancer Roundtable.

The disparities are striking:

• Only 34% of adults ages 45–49 are screened
• Just 24% of uninsured individuals are compliant
• Screening rates drop to 49% among those below the federal poverty level
• Rates are even lower among recent immigrants and those with less than a high school education

If we want to reverse rising cancer rates in younger adults, access and equity must be part of the conversation.

What About Cost?

Costs vary by region and insurance coverage. FIT is generally the most cost-effective strategy. Colonoscopy has higher upfront costs but longer intervals between tests. Multi-target stool DNA testing is more expensive than FIT and does not appear more cost-effective when performed every three years.

The American College of Gastroenterology recommends colonoscopy or FIT as primary screening methods based on overall clinical effectiveness and value.

A Community-Level Approach

At Oswego Health, we made colorectal cancer screening a mission. After tackling the pandemic-related backlog and reducing wait times, we partnered with primary care physicians to expand stool-based and blood-based screening access. Positive tests are promptly followed by colonoscopy.

We also launched a Direct Access Screening Colonoscopy program, allowing healthy individuals to schedule screening without an initial GI office visit—removing yet another barrier.

Because the truth is simple: the best screening test is the one that gets done.

Colorectal cancer is increasingly affecting younger adults. We have more screening tools than ever before. We know they work.

Now the challenge is making sure people use them.

Mohammad F. Ali, MD, FACG, FASGE, DABOM
Chief of Gastroenterology & Hepatology; Oswego Health