Colorectal cancer, the type that killed James Van Der Beek at 48, is lately looking a lot less like "Grandpa's disease." A new American Cancer Society analysis finds that nearly half (45%) of new colorectal cancer cases are now diagnosed in adults younger than 65, as rates continue to fall among seniors—progress largely credited to long-standing screening programs. Rates are rising not only in people aged 50 to 64, but also in those under 50, 75% of whom are diagnosed at stage 3 or 4, per the New York Times, perhaps owing to reduced screening. Only about a third of people aged 45 to 49 are getting screened, per NBC News. Rectal cancer in particular is ticking up about 1% per year across all age groups after years of decline.
Researchers see a generational pattern: people born in 1990 face about double the colon cancer risk and four times the rectal cancer risk of those born in 1950, per the Times. The analysis notes that the cancers appearing in younger groups are concentrated on the far side of the colon and rectum, hinting at different causes than in older patients. Suspected factors include shifts in the gut microbiome and inflammation linked to modern diets, microplastics, and antibiotics. Experts stress screening starting at 45 for average-risk adults and earlier for those with family history—and urge younger people to take symptoms like blood in stool, persistent bowel changes, abdominal pain, anemia, fatigue, or unexplained weight loss seriously.