Colorectal cancer rising fastest in children and young adults; new tumor atlas probes why

Right · 1Colorectal cancer is the second leading cause of cancer deaths in the US, and the New York Post reports that while rates have fallen for more than a decade in adults over 65, cases are rising among younger people. 1 Right · 1According to the Post, the increase within the under-50 group is most dramatic among children aged 10 to young adults in their early 20s: one study found a six-fold rise in ages 10 to 14 from 1999 to 2020, more than a quadrupling in ages 15 to 19, and nearly a doubling in ages 20 to 24. 1 Right · 1The disease remains very rare in people under 20, at about one case per 200,000 people a year and fewer than 100 diagnoses in US children annually. 1

Mixed · 2Both outlets say cancers in younger patients tend to be more advanced and harder to treat: the Post says a majority are diagnosed at Stage 3 or 4, and STAT says younger patients are often diagnosed later with more aggressive tumor features. 1 2 Right · 1In a study led by pediatric surgeon Dr. Erica Arnold, patients were diagnosed about 12 weeks after first symptoms, cancer returned in 37% of patients despite treatment, and 45% had died of the disease by the study's end. 1 Right · 1Gastrointestinal oncologist Dr. Christopher Lieu said delays in diagnosis may explain some of this but that the pattern suggests the cancers are "developing differently"; Arnold called it "a bit of a distinct disease" from that in older adults. 1

Right · 1The cause is unknown; experts quoted by the Post suspect ultra-processed food, inactivity, obesity, gut microbiome imbalances, antibiotic use and microplastics, with Lieu saying it may be a combination. 1 Centre · 1On Thursday 29 October, Dr. Kimmie Ng of the Dana-Farber Cancer Institute published a Nature Medicine study building a single-cell atlas of 189 colorectal tumors from patients in their 20s to 90s, which STAT says should help researchers control for variables that confounded earlier studies of how early-onset tumors differ. 2 Centre · 1Ng said survival for the very youngest patients, under 35, may be no better than for patients in their 40s or 60s despite more aggressive treatment and better baseline health, which is why researchers have long believed the tumors are biologically different. 2

Right · 1For symptoms, the Post cites Dr. Sandra Kavalukas of the University of Louisville as saying rectal bleeding in under-50s carries 8.5 times the likelihood of colorectal cancer and should prompt consideration of a colonoscopy; in Arnold's study the most common symptoms were back and abdominal pain (74%), bowel habit change (45.2%), weight loss (43%) and rectal bleeding (38%). 1