Rates of colorectal cancer (cancer of the colon or rectum) have been rising sharply among young and middle-aged Americans in recent years, even as they have been falling among people aged 55 and older — the age group usually associated with the disease, according to a study published Tuesday by the American Cancer Society (ACS).
A millennial born in 1990 is two times more likely to be diagnosed with colon cancer and four times more likely to be diagnosed with rectal cancer at any age in their life (not just after age 55) than a baby boomer born in 1950, the study found.
The absolute risk of developing colorectal cancer is still much, much lower for adults under the age of 55, but the trend is troubling.
“Trends in young people are a bellwether for the future disease burden,” said Rebecca Siegal, the study’s lead author and an epidemiologist for the ACS, in a released statement. “Our finding that colorectal cancer risk for millennials has escalated back to the level of those born in the late 1800s is very sobering.”
Colorectal cancer is the third most commonly diagnosed cancer among both men and women in the United States. In 2013, more than 113,000 Americans were diagnosed with the disease and almost 52,000 died from it, according to the Centers for Disease Control and Prevention.
This new study, which was published in the Journal of the National Cancer Institute, is the first one to analyze incidence trends for the disease by age group and time period since 1990, which is just before preventive screening for the disease began to be widespread.
Data for the study came from the records of 490,305 adults aged 20 and older who were diagnosed with colorectal cancer in the U.S. between 1974 and 2013.
The researchers’ analysis of this data revealed a trend that was quite positive: Colorectal cancer incidence rates dropped 32 percent between 2000 and 2013 among people aged 50 and older. That decline is likely the result of increased access to colonoscopy and other forms of preventive screening among this age group, say the researchers.
But the colorectal cancer incidence rate among younger adults has been going in the opposite direction, rising 22 percent between 2000 and 2013. The reasons for this increase are not entirely clear, say the researchers, but are likely related to skyrocketing rates of obesity as well as changes in lifestyle behaviors that pre-dated the obesity epidemic, especially unhealthy dietary patterns (more processed meat, less dietary fiber) and lower levels of physical activity.
Death rates for colorectal cancer followed similar trends after 2000, decreasing by 34 percent in people aged 50 and older, but increasing by 13 percent in younger adults.
What can be done
“Educational campaigns are needed to alert clinicians and the general public about this increase [in colorectal cancer among younger adults] to help reduce delays in diagnosis, which are so prevalent in young people, but also to encourage healthier eating and more active lifestyles to reverse this trend,” said Siegal.
Young adults are 58 percent more likely than older adults to be diagnosed with late-stage colorectal cancer, she and her colleagues point out in their study, primarily because the cancer “is typically not on the radar of young adults or their providers.”
That is a tragedy. For, when caught in its early stages, before it has spread beyond the colon or rectum, colorectal cancer is highly treatable.
A major obstacle in receiving an early diagnosis is access to medical care. People without insurance are unlikely to seek medical advice about the disease’s early symptoms.
In 2013, 22 percent of adults under the age of 55 were uninsured compared to 7 percent of those over that age, Siegal and her colleagues point out.
The Affordable Care Act (ACA) may help young people receive earlier colorectal cancer diagnoses, the researchers add. Tracking surveys have found that the proportion of adults aged 19 to 34 who were uninsured fell from 28 percent in 2013, just before the ACA’s first open enrollment to 18 percent in 2016, following its third open enrollment. A similar decline — from 18 percent to 11 percent— was also observed among adults aged 35 to 49 years.
Of course, that access to health care is now under threat by the Trump administration and Republicans in Congress, who are working toward a repeal of the ACA.
FMI: You can read the ACS’s report in full online in the Journal of the National Cancer Institute. You’ll find detailed information about colorectal cancer, including a list of its signs and symptoms, at the organization’s website.