New research finds rectal cancer deaths climbing much faster than colon cancer among younger Americans, and experts warn this gap will widen unless treatment and detection change. The study, which examined decades of death records and used machine learning to forecast trends, points to diagnostic delays, lifestyle factors, and regional differences as possible drivers. Certain groups, including Hispanic adults and residents of Western states, show the steepest rises, and projections suggest worsening outcomes for older millennials through 2035. The report raises hard questions about whether current screening and clinical approaches are keeping pace with a shifting disease pattern.
Researchers reviewed national death records stretching from 1999 to 2023 and fed that data into a machine learning model to estimate future mortality trajectories. Their work found that rectal cancer mortality is increasing two to three times faster than colon cancer among adults aged 20 to 44. That widening gap holds across demographics, signaling a broad and persistent trend rather than an isolated blip.
“Colorectal cancer is no longer considered predominantly a disease of older adults,” said lead author Mythili Menon Pathiyil, a gastroenterology fellow at SUNY Upstate Medical University. “Rectal cancer, especially, is becoming a growing problem in younger individuals.”
The projections are particularly worrying for people aged 35 to 44, where mortality tied to rectal tumors is expected to climb through 2035 if current trajectories persist. Hispanic adults and those living in Western states experienced sharper increases than other groups, suggesting socioeconomic, environmental, or access-related factors could be at play. These patterns hint that prevention and early detection efforts may not be reaching the people who need them most.
Clinicians and researchers point to delayed diagnosis as a major contributor to worse outcomes in younger patients. “Young people are being diagnosed with rectal cancers at increasingly younger ages — and often at more advanced, aggressive stages of disease,” Rachel Gordon, M.D., a New York-based colorectal and general surgeon at Episcopal Health Services, told Fox News Digital. Younger patients typically wait far longer for evaluation than older adults, turning manageable disease into a more dangerous problem.
On average, older adults begin treatment within a month of symptom onset, while young adults face an average seven-month delay before receiving care. Primary care providers may dismiss red-flag symptoms in younger people as benign issues like hemorrhoids, which leads to lost time and later-stage discoveries. That diagnostic inertia erodes the benefits of modern therapies and narrows options for curative treatment.
“We’re seeing a combination of lifestyle and environmental exposures, including diet and changes in the gut microbiome, potentially playing a role,” said Gordon, who was not involved in the study. Changes in diet, obesity trends, and shifts in microbial communities in the gut are under investigation as contributors to the rising incidence. While causation remains complex and multifactorial, the clues point to preventable or modifiable risks alongside biological shifts.
“If something doesn’t feel right, or if you experience symptoms such as rectal bleeding (bright red or dark), persistent changes in bowel habits (including diarrhea or constipation), narrow stools, a feeling of incomplete bowel emptying, abdominal pain, unexplained weight loss or fatigue, it’s important to see your doctor promptly,” Gordon advised. Early evaluation of these symptoms can catch disease at an earlier stage, when treatment is more likely to succeed. Clearer guidance for clinicians on when to escalate testing in younger patients could reduce harmful delays.
Investigators say the study’s findings demand a hard look at screening strategies and clinical thresholds. “Our study shows that rectal cancer is driving much of the increase in colorectal cancers,” she added. “It’s likely to worsen over time if we don’t change what we are doing right now.”
Health systems, primary care networks, and specialty providers face a choice: adapt practices to a shifting risk landscape or accept rising mortality among younger adults. That means better awareness, faster diagnostic pathways, and possibly revised screening guidelines targeted to where the data shows the greatest burden. Without actionable change, projections suggest this trend will become a long-term public health problem rather than a temporary anomaly.
