Nutrition
Colon Cancer in Young Adults: Surprising Factor Linked to Half of Cases, Study Finds
The increase in colon cancer cases among younger individuals has become a significant concern, with data revealing a startling trend. According to the American Cancer Society, the percentage of U.S. colorectal cancer cases in individuals aged 54 or younger rose from 11 percent in 1995 to 20 percent in 2019. This worrying pattern is not confined to the United States alone; at least 27 other countries have reported similar trends. If this trajectory continues, experts anticipate that colon cancer could become the leading cause of cancer-related deaths among young people by 2030.
In contrast, colon cancer rates and fatalities have been declining in those over 55, largely due to increased screenings and healthier lifestyle choices. This disparity has prompted scientists and doctors to investigate the underlying causes, with many pointing to the consumption of processed foods by younger generations as a potential factor.
A groundbreaking study published in the journal Nature has now identified a childhood factor that may be contributing to this rise in colon cancer among young people. The study highlights “a potential microbial culprit behind the alarming rise in early-onset colorectal cancer: a bacterial toxin called colibactin.”
Colibactin, a toxin produced by specific strains of E. coli in the colon and rectum, has the ability to alter DNA. Researchers analyzed 981 colorectal cancer genomes from patients across 11 countries, examining both early- and late-onset cancer cases. Their findings revealed that colibactin-related DNA mutations were 3.3 times more common in colon cancer cases under age 40 compared to those over age 70. Moreover, around 50 percent of colon cancer cases under age 40 exhibited evidence of colibactin exposure.
The study also found that colibactin-related mutations occur early in tumor development, consistent with previous research indicating that such mutations can arise within the first 10 years of life. These mutations account for 15 percent of APC driver mutations, which are among the earliest genetic alterations that directly promote cancer development in colorectal cancer.
“These mutation patterns are a kind of historical record in the genome, and they point to early-life exposure to colibactin as a driving force behind early-onset disease,” explained Ludmil Alexandrov, senior study author and professor at UC San Diego. “If someone acquires one of these driver mutations by the time they’re 10 years old, they could be decades ahead of schedule for developing colorectal cancer, getting it at age 40 instead of 60.”
While the study established a link between colibactin and colorectal cancer, it did not delve into the factors driving this exposure. In an interview with NBC News, Alexandrov suggested several possible explanations, including early-life antibiotic use, dietary changes such as increased consumption of processed foods or reduced fiber intake, higher rates of C-section births or reduced breastfeeding, and increased use of early group childcare, which could facilitate microbial transmission during a crucial developmental period.
“There are several plausible hypotheses,” Alexandrov stated. “Collectively these shifts may be tipping the balance towards early-life acquisition of these microbes.”
Further research is needed to understand how children are exposed to colibactin-producing bacteria. The researchers are particularly interested in exploring whether specific environments, diets, and lifestyle behaviors contribute to colibactin production.
In the short term, the research team is working on developing a stool sampling test to detect colibactin-related mutations. “The goal is to identify people who are at elevated risk for developing early-onset colorectal cancer, ideally before any disease has developed,” Alexandrov told NBC News. “We would want to have these people regularly checked.”
Additionally, the team is exploring the potential use of probiotics to eliminate these bacterial strains. “This reshapes how we think about cancer,” Alexandrov concluded in the press release. “It might not be just about what happens in adulthood—cancer could potentially be influenced by events in early life, perhaps even the first few years. Sustained investment in this type of research will be critical in the global effort to prevent and treat cancer before it’s too late.”
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