Colorectal Cancer Rates Climb Across Multiple Older Age Brackets
Colorectal cancer incidence is rising not just among younger adults, but across all age groups up to 65 to 69, according to a study published Oct. 27 in NEJM Evidence and reported by USA Today. While overall incidence rates fell from 55.2 per 100,000 in 2000 to 36.7 in 2022, they rebounded to 38.3 in 2023, driven by increases in older populations as well as the well-documented surge in patients under 50.
The sharpest annual increase occurred among adults aged 45 to 49, who saw a 12.76% annual rise from 2019 to 2023 using National Cancer Institute data covering a 20-year period, USA Today reported. Researchers attribute this specific spike to increased screening rates following national recommendations that lowered the starting age for routine colonoscopies from 50 to 45. Caitlin Murphy, study author and professor of pediatrics and public health sciences at the University of Chicago, noted that screening is performing as intended by catching cancer earlier, though she cautioned that unknown risk factors may be offsetting those diagnostic gains across other groups.
Distinct Cellular Patterns Discovered in Young-Onset Tumors
As epidemiological data reveals shifting demographics, a separate study published in Nature Medicine and reported by The Boston Globe and CBS News has identified fundamental biological differences in tumors from younger patients. Researchers analyzed 189 tumors and more than 850,000 individual cell nuclei from patients across the age continuum. According to Dr. Ana Anderson, a core faculty member and senior author at Brigham and Women’s Hospital’s Gene Lay Institute of Immunology and Inflammation, the objective was to explore whether the condition manifests differently in younger people compared to older patients.
Researchers Map Gene Expression Differences Across Age Groups
Rather than dividing samples into two rigid cohorts, the Nature Medicine research team looked for factors that changed gradually with age while accounting for tumor location, stage, sex, and prior treatment, Medical Xpress reported. This method uncovered subtle differences in gene expression that might have otherwise been obscured. Dr. Kimmie Ng, senior author and director of the Young-Onset Colorectal Cancer Center at Dana-Farber Cancer Institute, told The Boston Globe that the dataset is the largest of its kind for colorectal cancer and includes the highest number of young patients to date.
Dr. John Paul Shen, an associate professor of gastrointestinal medical oncology at the University of Texas MD Anderson Cancer Center who remained independent from the study, mentioned to The Boston Globe that this comprehensive cellular examination supplies a useful guide for future laboratory trials. Meanwhile, American Cancer Society data shows that colorectal cancer has climbed from the fifth-leading cancer death in the early 1990s to the leading cause of cancer-related death among people under 50 in the United States.
Common Questions About Colorectal Cancer Trends
What age groups are seeing rising colorectal cancer rates?
According to the NEJM Evidence study, incidence rates are increasing across all age groups up to 65 to 69, with the sharpest annual increase occurring in the 45 to 49 age bracket from 2019 to 2023.
Why did cancer rates jump among adults aged 45 to 49?
Study authors attribute the rapid increase in this demographic to more screenings after national guidelines lowered the recommended age to begin routine colonoscopies from 50 to 45, which successfully catches cancers earlier.
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