The trend is shaking doctors. Dr. John Marshall of Georgetown University’s Lombardi Comprehensive Cancer Center, who has been a cancer doctor for more than three decades, said he never saw colorectal cancer in people in their 20s, 30s and 40s early in his career. Now he does.
“We’re now starting to see more and more people in the 20-, 30- and 40-year-old range developing colon cancer,” Marshall said. “At the beginning of my career, nobody that age had colorectal cancer.”
The American Cancer Society estimates more than 158,000 cases of colorectal cancer will be diagnosed in the U.S. this year, and it will claim more than 55,000 lives. While cases and deaths have inched down overall in recent years, thanks in part to screening, the trend is moving in the opposite direction for younger adults.
Since the early 2000s, diagnoses in people under 50 have been rising. Last month, cancer society researchers reported that colorectal cancer mortality in Americans under 50 had increased by 1.1% a year since 2005, becoming the deadliest cancer in that age group. This year, the society estimates 3,890 people under age 50 will die of it.
Risk factors at any age include obesity, lack of physical activity, a diet high in red or processed meat and low in fruits and vegetables, smoking, heavy alcohol use, having inflammatory bowel disease or a family history of colorectal cancer. Marshall advises everyone to eat lots of fruits and vegetables and whole grains. “Meat’s not evil” but eat less of it, he said.
A recent study found that a three-year exercise program improved survival in colon cancer patients and reduced cancer recurrence.
Symptoms to watch for include blood in stool or rectal bleeding; changes in bowel habits such as diarrhea, constipation or narrowing of stool that lasts more than a few days; unintended weight loss; and cramps or abdominal pain. “Don’t ignore symptoms. Get it checked,” Marshall stressed. Survival is far more likely when colorectal cancer is diagnosed early, before it spreads.
Medical guidelines say the average person should start getting screened at age 45 — too late for some young adults. People known to be at higher risk are supposed to talk with their doctors about whether to start screening even earlier. How often people need to get checked depends on the type of screening they choose. There are a variety of options, including yearly stool-based tests or colonoscopies that may be done every 10 years as long as no problems were found. There’s also a newer blood test for adults 45 or older.
No one knows what’s causing the rise in cases in younger adults. Marshall said many young patients lack common risk factors. He wonders if changes in young people’s gut bacteria — the microbiome — might play a role.
Also, where cancer occurs along the question mark-shaped colon influences how aggressive it is and how it’s treated. Marshall said there’s a marked difference in where younger and older people’s tumors tend to strike, another clue being explored.