Becca Lynch put it down to stress. Pencil-thin bowel movements, five or six trips a day, then thick dark blood. She was 29. By the time she had a colonoscopy, months after the first signs, the diagnosis was stage 3B colon cancer.
The Guardian reported her story in March with fresh American Cancer Society findings: among Americans under 50, no cancer kills more of them than colorectal cancer. Since the 1990s it has climbed from fifth place to first. For people over 65 it the rate keeps dropping, by over two percent annually.
Rectal cancer is moving fastest
Within that trend, rectal deaths in younger adults are drawing particular attention. HuffPost, citing NBC’s reporting, said rectal cancer could become the top cause of cancer death under 50 by 2035 if nothing changes. Dr. Jatin Roper, a gastroenterologist at Duke Health, said rectal cancer is gaining ground more quickly than colon cancer. “We don’t know why,” he said.
Each generation is worse off than the last. Rates for people born in 2001 are higher than for those born in 1991, and those in turn top people born in 1981, the oldest millennials. Dr. Michael Foote of Memorial Sloan Kettering put the overall change in numbers: the colorectal cancer rate among under-50s is up 63% since 1988, from 8 to 13 cases per 100,000. He stressed that the disease is still rare in the young. What worries doctors is the slope.
The search for a cause
Nobody has pinned it down. Rebecca Siegel, who led the American Cancer Society analysis, calls it a birth cohort effect. Because risk rises with each generation born after the 1950s, she said, “there was some exposure, some risk factor that was introduced in the middle of the 20th century.”
Foote dates the start of the rise to somewhere between 1950 and 1990 and does not think extra screening explains it. He points to a Western diet heavy in animal fat, refined grains, processed sugar and red and processed meat, and to a food landscape that changed in those decades with fast food, more preservatives and plastic containers that carry microplastics. Roper added changes in the gut microbiome as another possibility, though he called the picture unclear. Obesity and diabetes raise risk, but Foote noted that most young patients have neither.
Symptoms get brushed off
Roughly three in four patients under 50 arrive with advanced disease, Siegel said, because they have not been screened and do not take symptoms seriously. Many assume haemorrhoids. Rectal bleeding is the most common sign of rectal cancer, and Foote said it is much more common in younger patients. Others are abdominal pain, thinner stools, constipation, fatigue, weight loss and anaemia. Some people have no symptoms at all.
Screening for average-risk adults starts at 45. Stool tests such as FIT and Cologuard are an option for those who cannot arrange a colonoscopy, and a positive result means a colonoscopy follows. Siegel urges anyone with rectal bleeding lasting more than a couple of weeks to see a doctor at once. She also wants oncologists to discuss fertility and sexual health ahead of treatment, because younger survivors often learn too late that they cannot have children.
Sources
- The Most Common Warning Signs Of Rectal Cancer
- Colon cancer now leading cause of cancer deaths under 50 in US
