By Sela Breen
Published: September 10, 2026
Main Facts
In recent years, the medical community has grown increasingly alarmed by a perplexing epidemiological shift: rates of early-onset colorectal cancer (CRC)—diagnosed in adults under the age of 45—have been steadily rising. Because standard screening guidelines historically targeted older populations, researchers and clinicians have been on an urgent quest to identify reliable, early warning markers that could flag high-risk individuals long before symptoms manifest.
Surprisingly, a major new analysis of more than 11,000 adult patients suggests that a crucial clue may have been hiding in plain sight within standard routine blood work: the basic liver panel.
Traditionally, patients and physicians alike view liver panels with a singular focus on elevated values. High readings of liver enzymes—specifically AST (aspartate aminotransferase) and ALT (alanine aminotransferase)—are universally recognized as red flags indicating liver stress, inflammation, or damage driven by factors such as non-alcoholic fatty liver disease, medications, or alcohol use.
However, a recent study conducted by Epic Research upends that conventional wisdom. The analysis reveals that low levels of AST and ALT—long dismissed as clinically insignificant or simply reflective of low muscle mass and poor nutritional status—are strongly associated with a significantly heightened likelihood of an early-onset colorectal cancer diagnosis in adults under 45.
Specifically, the data indicates that pre-screening AST levels below 14 U/L are linked to a 65% higher likelihood of developing early-onset colorectal cancer, while ALT levels below 14 U/L correlate with a 68% increase in likelihood. While these findings establish a compelling statistical association rather than a direct causative mechanism, they introduce an entirely new dimension to how clinicians might interpret routine metabolic blood panels in younger cohorts.
Chronology of the Finding
To understand how researchers arrived at this counterintuitive discovery, it helps to examine the timeline and methodology of the recent Epic Research investigation.
- The Rising Crisis (2020–2025): Over the past half-decade, oncology and gastroenterology journals have documented an undeniable surge in gastrointestinal cancers among Millennials and Generation Z. Public health agencies responded by lowering the recommended age for initial routine colorectal cancer screenings from 50 down to 45. Despite this adjustment, a significant percentage of early-onset cases continue to be diagnosed in patients well under 45, often at advanced stages because younger adults rarely suspect cancer.
- Data Pooling and Cohort Selection (Late 2025): Researchers at Epic Research set out to examine massive electronic health record repositories to determine if pre-diagnostic biomarkers existed in standard blood panels. They isolated a cohort of 11,469 U.S. adults aged 18 to 44 who were undergoing their first official colorectal cancer screening.
- Stratifying the Enzyme Ranges: The research team categorized the patients based on their baseline AST and ALT concentrations. Individuals registering between 14 and 29 U/L served as the control group. Those registering below 14 U/L were placed into the low, variable cohort.
- The Retrospective Window: Investigators cross-referenced these baseline liver enzyme panels drawn within the three years prior to screening against actual diagnostic outcomes. They specifically tracked patients who went on to receive a confirmed colorectal cancer diagnosis within one year of that initial screening.
- Publication and Announcement (September 2026): The findings were formally published, highlighting the dramatic statistical correlation between sub-14 U/L AST/ALT readings and early-onset CRC diagnoses, prompting widespread discussion across primary care and oncology sectors.
Supporting Data and Statistical Breakdown
The numbers underpinning the Epic Research analysis provide a stark look at the correlation between liver enzyme thresholds and early-onset colorectal malignancies.
- Sample Size: The study evaluated 11,469 U.S. adults falling within the 18-to-44 age bracket. Every participant had both documented lab results on file and a completed colorectal cancer screening, establishing a clear retrospective paper trail.
- The Threshold: The standard baseline control range utilized for the study was 14 to 29 U/L for both AST and ALT. Readings falling below 14 U/L were classified as low.
- AST Risk Elevation: Patients who exhibited an AST level below 14 U/L in the three years leading up to their screening demonstrated a 65% higher likelihood of an early-onset colorectal cancer diagnosis.
- ALT Risk Elevation: Similarly, patients with an ALT reading below 14 U/L faced a 68% higher likelihood of receiving a positive CRC diagnosis.
- Methodological Caveat: Researchers noted that because the participants possessed both lab work and completed screenings on record, the cohort likely skewed toward health-conscious individuals who engage with the healthcare system more frequently than the general population. This selection bias means the precise risk percentages should be interpreted within the context of a monitored clinical demographic rather than the population at large.
Clinical Perspectives and Expert Responses
The medical community’s response to the study has been a mixture of intrigue, caution, and calls for further investigation. Because liver enzymes have historically been studied strictly in the context of hepatology (liver health), seeing them cross over into oncology risk assessment requires a paradigm shift.
Understanding the Physiological Mechanism
Hepatologists and clinical pathologists point out that AST and ALT are intracellular enzymes found predominantly in the liver, but also in cardiac muscle, skeletal muscle, kidneys, and brain tissue. When these tissues experience high turnover, inflammation, or damage, enzymes leak into the bloodstream, elevating lab values.
Conversely, chronically low levels of these enzymes are frequently tied to factors outside primary liver pathology. Low AST and ALT are often clinical indicators of:
- Reduced overall skeletal muscle mass (sarcopenia or low muscle volume).
- Micronutrient deficiencies or poor baseline nutritional status.
- Altered metabolic states or systemic inflammatory conditions that suppress baseline enzyme production.
While these physiological factors do not directly mutate colon cells or cause tumors to grow, researchers hypothesize that they may serve as downstream systemic signatures of an underlying chronic metabolic or immunologic state that creates a permissive environment for oncogenesis.
The Cautionary Stance from Oncology
Leading oncologists emphasize that correlation is not causation. A single low blood test does not mean a patient has cancer, nor does it prove that low enzyme levels cause colorectal tissue to become malignant. Instead, experts suggest that low AST and ALT should be viewed as contextual variables—pieces of a larger clinical puzzle that includes family history, genetic predispositions, lifestyle factors, and gastrointestinal symptoms.
Implications for Patients and Clinical Practice
What does this mean for a young adult reviewing their routine metabolic panel? First and foremost, experts urge calm. A single lab value falling outside the traditional "normal" window on one isolated blood draw is never grounds for panic or an immediate diagnosis.
1. Shift from Single Draws to Longitudinal Trends
One of the most vital takeaways from the research is the power of tracking patterns over time. Reviewing a single set of blood work provides only a static snapshot. Examining how liver panels, metabolic markers, and complete blood counts shift across multiple years offers a far more accurate and nuanced view of systemic health trends.
2. Expanding the Preventive Conversation
For adults under 45, colorectal cancer screening has traditionally been a gray area. While high-risk individuals with strong family histories are monitored closely, average-risk young adults often slip through the cracks until symptoms like rectal bleeding, unexplained anemia, or persistent abdominal pain present themselves.
Integrating non-traditional markers like low AST and ALT into electronic health record algorithms could eventually help primary care physicians identify high-risk young adults who might otherwise be told they are too young to worry about colon cancer.
3. Actionable Steps for Patients
If you are an adult under 45 and notice that your liver enzyme numbers are trending low—or if you simply harbor concerns about colorectal cancer risk—experts recommend taking the following steps:
- Review the Full Panel with Your Doctor: Do not look at AST or ALT in isolation. Ask your primary care provider to walk you through your entire liver panel, metabolic profile, and how these figures have evolved compared to past annual physicals.
- Evaluate Your Complete Risk Profile: Discuss your family history of gastrointestinal cancers, lifestyle factors (such as diet, physical activity, and alcohol intake), and any persistent digestive symptoms openly with your physician.
- Stay Informed on Evolving Guidelines: The landscape of cancer diagnostics is moving rapidly. Non-invasive screening technologies, biomarker research, and preventative protocols are evolving every day, giving patients more proactive tools than ever before to stay ahead of early-onset malignancies.
The Bottom Line
The discovery that low liver enzymes can signal a heightened risk for early-onset colorectal cancer reminds us that clinical data often holds secrets we are only beginning to decode. Just as high values prompt investigation into hepatic stress, low values now demand our curiosity. By paying closer attention to longitudinal lab patterns and fostering open communication with healthcare providers, young adults can better navigate their long-term health and catch potential risks before they turn into emergencies.
