Rectal cancer deaths are rising at a significantly faster rate than colon cancer among younger Americans, a trend that researchers warn will continue to escalate without a shift in treatment.

Mortality rates for rectal cancer are growing two to three times faster than those for colon cancer among adults aged 20 to 44, according to a study to be presented at Digestive Disease Week 2026 in Chicago.

The data suggests that for older millennials, specifically those between the ages of 35 and 44, rectal cancer mortality is projected to escalate through 2035.

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“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 researchers analyzed Centers for Disease Control and Prevention (CDC) death records from 1999 to 2023. 

Using a machine learning model to project future trends, the team found that the mortality gap between the two types of cancer is widening across every demographic.

Hispanic adults and residents of Western states experienced the steepest increases in rectal cancer deaths, the study found.

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A primary concern raised by the research is the diagnostic delay often experienced by 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.

“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.

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Older adults tend to begin treatment within a month of symptoms starting — but young adults face an average seven-month delay before getting care.

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Pathiyil noted that primary care providers often dismiss red-flag symptoms in young people — such as rectal bleeding or changes in bowel habits — as benign conditions like hemorrhoids.

“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.

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The findings suggest that current screening strategies may need to be reevaluated, according to Pathiyil.

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“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.”

Early this year, I attended a longevity science conference in Miami hosted by the academy that Sinclair helped found. That weekend, about 65 scientists from around the world compared notes and waited in line for coffee and complained about the weather in the city, which was experiencing a freakish cold snap. Iguanas, stunned by the below-freezing temperatures, were falling from the sky, tumbling from their perches in trees and littering the sidewalks. Scientists wearing Oura rings and Apple watches skirted the tropical reptiles as they tried to get their 10,000 steps or maximize their high-intensity interval training. Others snapped photos to send to friends who were zoologists: Were the iguanas done for? Or might they be revived?

Becoming a member of the academy is an honor for longevity scientists, and protecting the group’s reputation was on the agenda for the first day of discussion. Its leaders had come to believe that they had a P.R. problem, as groundbreaking research like cellular rejuvenation gets mixed up, in the public’s mind, with businesses selling unproven supplements and billionaires like Bryan Johnson grabbing headlines by infusing himself with his son’s blood. “There are too many terms, too little clarity, mixed messaging, public confusion and so on,” Nir Barzilai, a professor at the Albert Einstein School of Medicine and the academy’s president, told the crowd.

Barzilai, who is known for his work exploring longevity genes in centenarians, went on to introduce a branding consultant he hired, who warned the group that there was a misalignment between the work they were doing and “the fringe anti-aging approaches” and the “snake oil” that did the field harm. After some debate, the group voted to rebrand itself the Academy of Geroscience — the name the consultant recommended. (“Geroscience” literally means “the science of aging.”) Ringel, the Life Biosciences executive, seemed undecided about the name — he wasn’t sure it captured the great potential of the field to transform the human life span.

The conference showcased the debate that longevity researchers — or geroscientists — are having about how to set expectations for the public. Until he joined Altos, Juan Carlos Izpisua Belmonte, like Sinclair, had been known to make grand proclamations about just how much life extension we could anticipate and how soon: In 2019, Izpisua Belmonte told MIT Technology Review that he believed there was probably already an individual born who would live to be 130; humans, he said, might eventually live 50 years beyond our current life span.

By contrast, Barron, the Altos chief executive, shies away from that sort of prediction. He fears that others in the field are raising expectations so high that the public might not recognize a miracle of progress when it occurs. Even if we cured all cancer tomorrow, Barron said, we’d add maybe only two or three years to the average American’s life span. “So if we extend health span by three years,” he said, “you’re doing the equivalent of something which will not happen anytime soon, which is curing cancer.” Should Altos manage to add five years to life expectancy — more than Barron even could hope for, he said — he feared that the public would still be disappointed. “Even delaying ovarian aging by three years or Alzheimer’s by three years — that would be transformative,” he said.

New research is suggesting a strong association between mouth bacteria and gastric cancer.

The study, published in the journal Cell Reports Medicine, examined the gut microbiome in stool and the oral microbiome from saliva and the tongue.

The China-based researchers with BGI Genomics analyzed 404 samples from Chinese patients with gastric cancer in one group and chronic gastritis in another.

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Gut microbes were different in gastric cancer, the researchers found, unveiling 28 varying gut species. 

Most were oral bacteria, including Streptococcus — bacteria that can sometimes cause strep throat — lactobacillus and other lactic acid bacteria.

Twenty oral-gut species were found in both saliva and stool and were more common in the gut of gastric cancer patients.

The findings suggest the transmission of these bacteria from mouth to gut, after finding that the oral bacteria matched closely to the gut bacteria in the same person, according to genetic comparisons.

The researchers suggest that saliva and stool samples could help indicate patterns that are linked to stomach cancer, although more research is required before testing is ready for clinical use.

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“Collectively, these findings underscore the critical role of the oral-gut microbiome axis in [gastric cancer],” the researchers concluded in the study publication.

Since this is a cross-sectional analysis, the results cannot prove that these bacteria cause cancer, but they do suggest a strong association.

Dr. Brian Slomovitz, director of gynecologic oncology and co-chair of the Cancer Research Committee at Mount Sinai Medical Center in Miami Beach, Florida, talked about the “initiator-promoter” model of this study in an interview with Fox News Digital.

“[The study] demonstrates how the microbiome of one area of the body can migrate and affect the ability of cancers to develop in another part of the body,” said Slomovitz, who was not involved in the new study. 

“It is very important that we work toward a healthy microbiome in the gut to decrease the risk of inflammation and cancer.”

“The initiator in gastric cancers is usually inflammatory, such as H.pylori infection,” he continued. 

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“This inflammation leads to damaged mucosal cells where the lactic acid-producing bacteria can colonize. This helps to explain why cancers still develop even after treating H. pylori infection.”

The new findings could be applied to using the saliva for early cancer detection, Slomovitz suggested, which may help identify the disease even in pre-cancer states.

“Perhaps we will learn that by altering the microbiome, we can help better treat cancers (in combination with immunotherapy or chemotherapy) or even prevent cancer,” he said. 

“These results will build a foundation for future research. However, we are not ready to incorporate this into clinical practice.”

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Fox News senior medical analyst Dr. Marc Siegel also weighed in separately on the study, noting that awareness around the importance of the gut microbiome on overall health has been growing.

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“There is a correlation between the bacteria found in the gut and neurogenerative disease and increased cancer risk,” he told Fox News Digital. 

“It is very important that we work toward a healthy microbiome in the gut to decrease the risk of inflammation and cancer.”