I led a study published today that suggests the next breakthrough in colorectal cancer could be finding precancerous lesions that may turn into malignant tumors.
In an international study published in The Lancet Gastroenterology & Hepatology involving more than 1,600 participants, my colleagues and I developed a blood-based test that detected 91% of colorectal cancers and 81% of advanced adenomas, the precancerous growths that often represent the last step before cancer develops.
Because identifying and removing these lesions can prevent colorectal cancer from occurring, they have become a major focus of screening efforts. Yet advanced adenomas have remained one of the most difficult targets for blood-based tests to detect.
The urgency is growing:
- More than 158,000 Americans are expected to be diagnosed with colorectal cancer in 2026, and over 55,000 are expected to die from the disease.
- Colorectal cancer rates among adults younger than 50 have been increasing by nearly 3% annually since 2013.
- Most colorectal cancer deaths still occur in people who have never been screened.
Those trends make one thing clear: we need screening tools that meet people where they are and make early detection more accessible.
A Missing Piece in the Blood-Test Revolution
Blood-based colorectal cancer screening is no longer a future concept. In 2024, the U.S. Food and Drug Administration approved the first blood-based screening test for colorectal cancer in average-risk adults, reflecting growing confidence that a simple blood draw could help increase screening participation among millions of Americans.
That approval marked a major milestone. But it also highlighted a challenge that researchers across the field continue to confront.
Most blood-based tests currently available or under development were designed primarily to detect existing cancers. Advanced adenomas may develop years before cancer is diagnosed, creating a valuable window for intervention. These precancerous growths are a major blind spot because they don't shed the same strong signals into the bloodstream as fully developed cancers, making them much harder for blood-based tests to find.
Our team approached the problem differently by making advanced adenomas central to our research strategy from the start.
Rethinking How Blood Tests Are Designed
Historically, many researchers have searched for biomarkers that distinguish people with cancer from those without cancer. Only later do they evaluate whether those same biomarkers can also identify precancerous lesions.
Our study reversed that process.
We deliberately incorporated advanced adenomas into every stage of test development, from biomarker discovery through machine-learning model training. By studying both colorectal cancer and its precursors, we aimed to build a test that could recognize the molecular changes that occur along the entire pathway from precancerous growth to invasive cancer.
The result was a blood test that analyzes dozens of small molecular signals called microRNAs, which are found freely circulating in the bloodstream and within exosomes, tiny particles released by cells. Together, these signals provide a detailed picture of biological activity occurring within the body.
In the validation phase of the study, the assay:
- Detected 91% of colorectal cancers
- Detected 92% of stage I-III colorectal cancers, when treatment is often most effective
- Detected 81% of advanced adenomas, the precancerous growths most likely to become cancer
These findings suggest that blood-based screening may be capable of identifying both existing cancers and the precancerous lesions that often precede them, bringing us closer to a screening approach that emphasizes prevention as much as detection.
What This Could Mean for Patients
It's important to emphasize that colonoscopy remains the gold standard for colorectal cancer screening. Colonoscopy finds abnormalities and allows physicians to remove precancerous growths during the procedure. Current screening guidelines still recommend that average-risk adults begin screening at age 45.
But we also know that many eligible individuals never complete recommended screening. Some face logistical challenges. Others avoid existing tests because of inconvenience, discomfort or competing priorities. Blood-based screening may help bring more people into the screening process, particularly those who might otherwise remain unscreened.
For patients, the numbers matter only if they lead to something meaningful: fewer cancer diagnoses, less treatment and better outcomes.
Much work remains before this approach could become part of routine clinical care. Larger prospective studies are needed to evaluate how the test performs in real-world screening populations and how it might complement existing screening options. We are now focused on generating that evidence and continuing to refine the science.
If future studies confirm these findings, the impact could be substantial. A routine blood draw during an annual medical visit could help identify people with high-risk precancerous lesions long before symptoms appear, giving physicians an opportunity to intervene earlier and prevent cancers that might otherwise develop.
For patients and families, that future could mean fewer cancer diagnoses, fewer lives disrupted by treatment and more opportunities to stop colorectal cancer before it starts.
About the Author
Ajay Goel, Ph.D., AGAF, is professor and chair of the Department of Molecular Diagnostics and Experimental Therapeutics at City of Hope and associate director of basic science for City of Hope Comprehensive Cancer Center. He is an internationally recognized expert in gastrointestinal cancers. His research focuses on developing blood-based tests and other precision medicine approaches to detect cancer earlier and improve patient outcomes.
Funding
This study was supported by grants from the National Cancer Institute (CA72851, CA181572, CA184792, CA187956, CA202797, CA214254, CA271443, CA296639, CA299594) of the National Institutes of Health (NIH) and by a Start-Up grant (No. 32233) from the AIRC Foundation.