A landmark study presented at the 2025 American Society of Clinical Oncology (ASCO) Annual Meeting has revealed striking racial and ethnic disparities in early-onset colorectal cancer, with minority populations facing disproportionate burden and advanced-stage diagnoses. The research, conducted by Ontada using data from 105,000 patients across one of the largest community oncology networks in the United States, represents one of the most comprehensive analyses of early-onset colorectal cancer to date.
Disproportionate Impact on Minority Populations
The study identified significant overrepresentation of certain racial and ethnic groups among patients diagnosed with colorectal cancer before age 50. Black patients comprised 11% of early-onset cases compared to only 8% of average-onset cases, while Hispanic and Latino patients represented 12% of early-onset diagnoses versus 8% of later-onset cases. American Indian and Alaskan Native populations also showed higher representation in the early-onset group at 1.3% compared to 0.9% in average-onset cases.
"We found overrepresentation of patients of American Indian and Alaskan Native race as well as Asian and Black race and Hispanic and Latino ethnicity in the early-onset group," explained Jessica Paulus, ScD, senior director of observational research at Ontada and lead researcher on the study.
Advanced Stage at Diagnosis Creates Survival Concerns
Perhaps the most clinically significant finding was the stage distribution at initial diagnosis. Early-onset patients demonstrated a concerning shift toward more advanced disease, with 37% presenting at stage III compared to 34% in average-onset patients, and 34% presenting at stage IV versus 28% in the older cohort. This represents approximately a 10 percentage point greater likelihood of advanced-stage diagnosis for younger patients.
"The early-onset patients were more likely to be diagnosed at stage 3 and stage 4 disease, again, at that initial diagnosis, as compared to the patients with an average onset of disease," Paulus noted. "We found about a 10% point difference in that early-onset cases had about a 10% greater chance of being diagnosed at stage 3 or 4 at initial diagnosis."
The implications for patient outcomes are profound, as the research confirmed that initial stage at diagnosis serves as the strongest predictor of overall survival for all colorectal cancer patients, regardless of age at diagnosis. Despite this concerning stage shift, the 5-year overall survival probability was 72% for early-onset patients compared to 64% for average-onset patients.
Current Screening Guidelines Fall Short
The study highlighted critical gaps in current screening approaches. With screening guidelines recommending initiation at age 45, over half of early-onset patients—particularly those under 44—remain outside the screening paradigm. "Half of our early-onset patients were actually younger than age 45 at diagnosis, so they are not being helped by those current population-level screening," Paulus emphasized.
Diagnostic Delays Compound the Problem
The research revealed that younger patients experience significantly longer diagnostic delays, with intervals of 4-8 months between first symptoms and definitive diagnosis compared to older patients. This delay contributes to the advanced-stage presentation observed in early-onset cases.
"From other research, we know that there is a greater diagnostic delay for the early-onset patients," Paulus explained. "I noticed a study that suggested that the early-onset patients had a 6-month greater duration from time of first symptom to definitive diagnosis as compared to patients who are older with colorectal cancer."
Additional Risk Factors and Patient Characteristics
The study identified several additional characteristics distinguishing early-onset patients. Obesity rates were higher in the early-onset group at 36% compared to 31% in average-onset patients. Early-onset patients were also more commonly located in urban areas (69% versus 63%) and reported higher levels of psychological distress, with 29% experiencing high or moderate distress compared to 22% in the average-onset group.
Clinical Practice Implications
The findings underscore the need for fundamental changes in clinical practice and screening approaches. Paulus advocated for risk-based screening models similar to those successfully implemented for non-small cell lung cancer, which could identify younger patients warranting low-threshold colonoscopy referrals.
"We've got to figure that out. This is really a challenge for practitioners in the internal medicine or general medicine space before these patients get to oncology practice to consider how to reduce the time from symptom to diagnosis," she stated.
The research also points toward the potential value of noninvasive or less-invasive screening approaches for younger populations, particularly given the diagnostic challenges and delays currently experienced by early-onset patients.
Addressing the Growing Epidemic
The study comes amid growing recognition of what researchers term an "epidemic" of early-onset colorectal cancer, with rising rates observed not only in the United States but globally, including in low- and middle-income countries. The comprehensive analysis of 15,000 early-onset cases within the larger cohort provides unprecedented insight into the scope and characteristics of this emerging public health challenge.
The research emphasizes that earlier detection remains critical for all patients, given the dire prognostic consequences of advanced-stage disease at initial diagnosis. However, the documented disparities in early-onset cases demand targeted interventions to address both screening gaps and diagnostic delays that disproportionately affect younger patients from minority communities.
