Why is colon cancer rising in young Americans?
Incidents of the disease in people under 50 are up significantly
The five people gathered around the restaurant table do not fit the profile of colon cancer patients. They’re female, and they’re young. Two were diagnosed in their 20s, one in her 30s, two in their early 40s.
Their colon cancer support group gathers about once a month to share stories, such as the one about the doctor who said you just need a laxative, the one about the oncologist who said there’s nothing we can do for you but give you chemotherapy the rest of your life, the one about friends saying, “You don’t look sick,” without realizing that isn’t helpful.
“It’s making themselves feel better,” said Carly Brown, 29, a schoolteacher diagnosed with Stage 4 colon cancer five years ago.
These women know all too painfully well that something strange is happening in the United States in the long war on cancer. Although progress has been substantial in lowering the overall death rate from cancer, deaths due to some types of cancer have increased among people younger than 50.
Colorectal cancer is one of the drivers of this trend.
A report released early this year by the American Cancer Society found that people younger than 55 went from accounting for 11% of all colorectal cancer in 1995 to 20% in 2019. About 3,750 people younger than 50 will die of colorectal cancer in 2023, according to the report.
The rise in early-onset colorectal cancer is driven primarily by cancer forming on the patient’s left side, in the lowest portion of the colon or the adjacent rectum, said Rebecca Siegel, senior scientific director of surveillance research for the American Cancer Society. These cases tend to be more advanced than cancers detected in older people.
Siegel first spotted statistical evidence of the phenomenon in early 2008 and wrote a report published in 2009. Further studies showed that, contrary to what some experts suspected, this is not just a case of increased screening and earlier diagnosis, Siegel said. Mortality rates have been increasing alongside disease incidence, she said.
“This is a dramatic increase. And the trends are not going away,” said Whitney Jones, a gastroenterologist who founded the Colon Cancer Prevention Project in Louisville and now is a consultant for Grail, the liquid biopsy company. “We need to educate all people around colorectal cancer, similar to how we educate women around breast cancer.” Colorectal cancer remains a relatively uncommon disease among young people. But that creates a diagnostic hurdle: When a young woman, for example, tells a doctor she’s experiencing severe pain in her lower abdomen, or blood in her stool, or unexplained weight loss, the doctor probably isn’t going to think “colon cancer.”
A common symptom among patients with colorectal cancer is rectal bleeding, and such patients are usually diagnosed with hemorrhoids, Siegel said. Doctors “are thinking horses, not zebras.”
The rise in colorectal cancer among young people has been seen in other highly developed countries as well, Siegel said.
One suspected factor is obesity, which has soared among children and young people. Lifestyle changes that increase the risk of being overweight, such as increased consumption of highly processed, low-fiber foods and a lack of exercise, could be boosting the risk of colorectal cancer.
Researchers note, however, that many young colorectal cancer patients have no history of obesity. That suggests that more subtle, systemic factors could be at work, such as changes in gut bacteria — the microbiome — according to medical experts.
The dismaying reality is that multiple factors are taking the lives of people who have not yet reached a ripe old age. Colorectal cancer is a tiny element in that complex story, but the recent rise in the disease among seemingly healthy young people is a reminder the health landscape is constantly evolving in ways not readily understood by medical science.
For now, this is a medical mystery. Emily Domhoff, 30, another member of the group, has given up trying to figure out why she has Stage 4 colon cancer despite having no obvious risk factors: “It could be totally random. I’m not sure. I kind of have to let it go for my own sanity.”