The updated guidance also introduces two new stool-based tests as “preferred” options while cautioning that positive results from any non-colonoscopy test require follow-up within six months, a step that real-world data shows half of patients fail to complete. For a generation taught to trust screening as a life-saving intervention, these findings demand a closer look at what the guidelines actually say versus what the medical establishment has promoted.
Key points:
- The American Cancer Society updated colorectal cancer screening guidelines for the first time since 2018.
- Blood-based liquid biopsy tests are not recommended as preferred screening due to low sensitivity for precancerous lesions.
- Two new stool-based tests, ColoSense and Cologuard Plus, have been added as preferred screening options.
- The age-45 screening start recommendation remains in place amid rising early-onset colon cancer rates.
- Racial and ethnic disparities in colon cancer incidence and mortality remain severe.
American Cancer Society admits liquid biopsies often miss a proper diagnosis
The most striking admission buried within the new guidelines concerns blood-based screening tests, often called liquid biopsies. These tests analyze cell-free DNA in the bloodstream and have been marketed as a convenient alternative to stool sampling or invasive colonoscopies. But the ACS now states bluntly that these tests “are not recommended as preferred screening options at this time.” The reason is straightforward. Two large prospective studies, the ECLIPSE and PREEMPT CRC trials, found that blood-based tests detected only about 13% of advanced precancerous lesions, meaning 87% of dangerous growths that could become cancer were missed. The entire logic of screening, as the guidelines themselves note, rests on the principle that 80% of the long-term mortality benefit comes from finding and removing those precancerous lesions before they turn malignant. A test that misses most of them cannot claim to be a prevention tool.
The specificity problem grows worse with age. In both major studies, the rate of false positives among adults aged 70 and older jumped to roughly 20%, compared with under 10% for those younger than 55. This means older patients, who face the highest risks from follow-up colonoscopy complications including bowel perforation, bleeding, and adverse reactions to sedation drugs, are most likely to be told they have a problem when they do not. The ACS does acknowledge that blood-based tests have value for people who would otherwise refuse any screening, but the language is cautious. These tests are described as a last resort, not a first choice.
New stool tests utilize an algorithm for enhanced detection
Two newly approved stool tests now join the preferred list: ColoSense and Cologuard Plus. The ColoSense test uses an algorithm combining eight RNA biomarkers, a fecal immunochemical test, and self-reported smoking status. Its validation study showed 94.4% sensitivity for colorectal cancer and 100% sensitivity for stage I disease, but only 45.9% sensitivity for advanced adenoma.
The Cologuard Plus test, an updated version of the original Cologuard, showed 93.9% sensitivity for cancer and 43.4% for advanced precancerous lesions. Both require testing every three years and are now considered equivalent to annual high-sensitivity stool blood tests in the ACS modeling studies. However, with enhanced, high sensitivity testing and predictive algorithmic cancer screening comes the possibility of false positives, pushing patients into expensive and needless cancer treatment protocols.
Without proper follow-up, mis-diagnosis rates rise
A critical detail that often gets lost in media coverage is the requirement for follow-up colonoscopy after any positive non-colonoscopy test. The guidelines are explicit that a positive stool or blood test is not a diagnosis and cannot be followed by another non-colonoscopy test. This may sound obvious, but real-world data show it is a genuine problem. One randomized trial cited in the guidelines found that only 50% of participants with a positive blood-based test completed a follow-up colonoscopy within six months, compared with 70% of those with a positive fecal test. That gap matters because a positive screening result without follow-up leaves the patient in medical limbo, neither screened nor diagnosed, and potentially with a growing lesion that remains untreated.
The decision to maintain the age-45 screening start age, first introduced in 2018, is backed by troubling epidemiological data. Colorectal cancer incidence in adults under 50 increased by 3% per year between 2013 and 2022. Among Americans younger than 50, colorectal cancer is now the leading cause of cancer death in men and the second leading cause in women. Research has linked dietary factors, particularly in younger women, to this alarming rise. Yet screening uptake among the newly eligible age group remains low, with only 37% of adults aged 45 to 49 reporting they are up to date with recommended screening as of 2023.
Disparities and lack of prevention guidance
The disparities section of the guidelines paints an even starker picture. Black Americans face an 11% higher incidence rate and a 40% higher mortality rate from colorectal cancer compared with white Americans. American Indian and Alaska Native populations face a 48% higher incidence rate and a 44% higher mortality rate. Alaska Native people specifically have more than double the incidence and mortality rates of white populations. These numbers exist alongside persistent gaps in screening access tied to insurance status and socioeconomic factors. The guidelines acknowledge that the anticipated high cost of newer tests will represent a significant barrier for uninsured and under-insured populations.
To make matters worse, the medical establishment is not forthright about simple preventative measures for these demographics. Simple interventions like vitamin D prove effective especially for darker skin colors. Diets rich in fiber and phyto-nutrients are rarely suggested, as colorectal cancer cases rise. There remains no mention of the role nutrition and lifestyle changes can play in preventing colorectal cancer, despite decades of research linking diet, exercise, and environmental exposures to colon cancer risk. The ACS has been notably silent on this front, continuing to emphasize screening and intervention over prevention.
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