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Key Points:

• Early-onset colorectal cancer (EO-CRC) is on the rise, with younger patients more likely to be diagnosed at advanced stages, which significantly impacts survival outcomes.
• EO-CRC is associated with notable racial and ethnic disparities, greater psychosocial distress and unique care burdens compared to average-onset cases.
• This trend highlights the urgent need for improved and earlier colorectal cancer screenings targeted at high-risk, younger individuals and the importance of tailored support and early engagement for those navigating cancer care.
• The study calls for cross-disciplinary approaches and further investigation into the drivers of diagnostic delays and advanced disease in younger populations, emphasizing the need for health systems to adapt screening and support strategies to address these emerging challenges in community oncology.

Colorectal cancer is increasingly affecting younger adults, even as rates among older populations decline. While diagnoses in people age 50 and older have decreased, incidence continues to rise among those under 50 — highlighting early‑onset colorectal cancer (EO-CRC) as a distinct and growing challenge.

This shift is drawing increased attention from families, communities, clinicians and researchers, raising the important question: Why are more young adults being affected? As factors like lifestyle, diet and environmental exposures are thought to play a role, it’s the real experiences of younger patients that are critical to shed light on the causes. Real-world evidence (RWE) is giving scientists and healthcare professionals crucial clues about what’s driving this surge.

Researchers at Ontada, a ²ÝÝ®ÊÓƵ company focusing on oncology technology and insights, dove into real-world data from community oncology practices across the U.S. Their goal: to better understand the social determinants and clinical factors that shape health and clinical outcomes among patients diagnosed with EO-CRC. In this analysis, social determinants refer to everyday circumstances for patients that influence a person's health, wellbeing and quality of life, such as where they live, how they enter the healthcare system and the type of challenges they report at diagnosis. The findings shine a light on the need to better understand, support and advocate for this younger generation now facing a diagnosis that upends their lives.

Below are key takeaways from their research, which was presented at the 2025 American Society of Clinical Oncology (ASCO) Annual Meeting:

How does stage at diagnosis differ between early‑ and average‑onset colorectal cancer?

Takeaway: Earlier detection matters for all patients with colorectal cancer, yet EO-CRC patients are more likely to be diagnosed at advanced stages. In this real-world cohort, 71% of EO-CRC cases were stage III or IV at diagnosis, compared with 62% of average-onset CRC. This pattern highlights persistent challenges in timely recognition among younger patients and reinforces the importance of improving pathways to earlier diagnosis across age groups.

Which populations are disproportionately represented among EO-CRC patients?

Takeaway: The EO-CRC cohort shows heightened disparities by race and ethnicity, with patients of Black, Asian and American Indian/Alaskan Native race and Hispanic ethnicity overrepresented in patients diagnosed at younger ages. This finding signals an urgent need for inclusive trial designs, targeted outreach and equitable access strategies.  These disproportions suggest that everyday factors that influence cancer risk and care should be reflected in research design and outreach approaches, as well as community partnership planning, from the outset.

What non-medical factors and lifestyle signals stand out?

Takeaway: EO-CRC patients are more likely to live in urban areas and have higher obesity prevalence, while smoking rates are similarly low across age groups. These signals argue for building social and neighborhood level factors and metabolic risk markers into prediction and outreach models to identify individuals who may be at higher risk for EO-CRC, and who would benefit from more robust screening.

How does patient reported distress differ for EO-CRC?

Takeaway: Younger patients report greater psychosocial burden, reinforcing the value of early palliative, navigation and behavioral health supports. Even measured in a subset, these differences justify operational investments in screening for distress and linking EO-CRC patients to supportive resources.

What do survival outcomes look like in EO-CRC vs AO-CRC?

Takeaway: EO-CRC patients are more likely to be diagnosed at advanced stages, and across age groups, stage at diagnosis is the strongest predictor of overall survival. These findings underscore the importance of early detection and entry into care and point to the need for further investigation into the reasons that younger patients are experiencing diagnostic delays and other drivers of more advanced disease at diagnosis.

What this means for care delivery

Taken together, these findings show that EO-CRC is associated with racial and ethnic disparities, higher reported patient distress, and more frequent advanced stage disease at diagnosis—which remains the single most important predictor of poor survival. For health systems and care partners, this data reinforces the value of earlier engagement and tailored, informed support for a younger patient population navigating cancer care and cancer screening. Most importantly, it highlights the critical need for improved colorectal cancer screenings for younger, high-risk patients. By identifying and screening these individuals earlier, we can reduce the chances of late-stage diagnoses and significantly improve survival outcomes. Tailored screening strategies are essential to ensure younger patients at risk are not overlooked and receive timely, effective intervention.

About the dataset:

Retrospective cohort from  EHR across The US Oncology Network and non‑Network community practices (2000–2024), representing >2,500 community-based providers caring for >1.4M patients annually; 104,281 CRC patients were identified and categorized as EO‑CRC if diagnosed <50 years (others = average‑onset, AO‑CRC). Overall survival (OS) was estimated via Kaplan–Meier. Research sponsor: Ontada®.

• Data source: iKnowMed® EHR; cohort window 2000–2024 across The US Oncology Network and non‑Network practices; OS via Kaplan–Meier.
• Sample sizes: EO‑CRC n=14,611; AO‑CRC n=89,670; Distress Thermometer subsample n=2,810
• The study team concludes EO‑CRC is an emerging concern in community oncology with heightened disparities and unique care burdens, warranting tailored, cross‑disciplinary approaches and further investigation into non-medical and clinical factors that shape health outcomes.