Early-Onset Colon and Rectal Cancers Show Distinct Patterns in US Inpatients
Key Clinical Summary
- A retrospective analysis of 2020–2022 US inpatient data identified 50,270 adults younger than 45 years with colorectal cancer: 57.4% had colon cancer and 42.6% had rectal cancer.
- Rectal cancer was associated with higher odds of lung or pleural, bone, and brain metastases. Colon cancer more often presented with bowel obstruction or perforation.
- The ACG 2026 poster authors called for research into separate, risk-adapted diagnostic and screening strategies for early-onset colon and rectal cancer.
An analysis presented at the 2026 American College of Gastroenterology meeting found different clinical patterns among younger adults hospitalized with colon cancer and those with rectal cancer. Using the Nationwide Inpatient Sample, investigators compared patients younger than 45 years by cancer site, including their comorbidities, presentation characteristics, and metastatic patterns. The presentation received an ACG Presidential Poster Award.
Study Findings
The retrospective cohort study used Nationwide Inpatient Sample data from 2020 through 2022. Investigators identified adults with colon or rectal cancer using ICD-10 codes and compared groups through bivariate analysis and multivariable logistic regression.
Of 50,270 adults younger than 45 years with colorectal cancer, 28,865 (57.4%) had colon cancer and 21,405 (42.6%) had rectal cancer. Patients with rectal cancer were slightly older and more often male than those with colon cancer (55% vs 51%; P<.001).
Metastatic patterns also differed by site. Rectal cancer was associated with higher odds of lung or pleural, bone, and brain metastases. Colon cancer more frequently presented with bowel obstruction and perforation; the adjusted odds ratios for rectal versus colon cancer were 0.67 and 0.69, respectively.
Colon cancer showed stronger associations with obesity, gastroesophageal reflux disease, and cirrhosis. Rectal cancer showed stronger associations with male sex, Asian race, and Crohn disease.
Clinical Implications
The findings give clinicians site-specific details to consider when evaluating early-onset colorectal cancer. In this hospitalized population, colon cancer more often involved obstruction or perforation, whereas rectal cancer had a greater association with the reported extra-abdominal metastatic sites.
The authors suggested that the rising burden of rectal cancer in younger people, together with its metastatic profile, makes timely diagnosis especially consequential. They proposed exploring separate, risk-adapted screening and diagnostic strategies for early-onset colon and rectal cancer. The inpatient study did not test such strategies or establish whether different approaches would improve outcomes.
The authors also emphasized careful inspection of the distal rectum during endoscopy, including retroflexion when feasible. Their recommendation reflects concern that subtle rectal lesions could otherwise be missed.
Expert Commentary
Presenting author Samyak Dhruv, MD, of Geisinger Wyoming Valley Medical Center in Wilkes-Barre, Pennsylvania, and colleagues wrote that the findings support moving beyond a single “colorectal cancer” framework. “For endoscopists, meticulous rectal examination remains essential,” they stated, specifying careful distal rectal inspection and retroflexion when feasible.
The US inpatient analysis identifies differences between early-onset colon and rectal cancer in presentation, associated conditions, and metastatic sites. Further research would be needed to determine how those differences should inform screening or diagnostic pathways.
Reference: Dhruv S, Boger J, Deivert D, et al. Reconsidering early-onset colorectal cancer as a single entity: colon vs rectal cancer in adults younger than 45 years. Poster P5018. Presented at: American College of Gastroenterology Scientific Meeting 2026; Nashville, Tennessee. October 13, 2026.
