Rates of colorectal cancer are rising among U.S. residents under 50 years old, according to a study published last month in the journal Cancer, leading some provider groups to lower their recommended screening age for the disease.
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Colorectal cancer rates increasing among younger adults
Colorectal cancer is the third-most common cancer diagnosis among U.S. men and women, and is particularly prevalent among older adults, according to the American Cancer Society (ACS).
While rates of death from colorectal cancer have been falling overall in the United States, the rate of colorectal cancer diagnoses and deaths among younger adults have been increasing over the past decade.
For the study published last month, researchers from the University of Texas-Austin set out to assess changes in the proportion of colorectal cancer cases diagnosed among adults younger than 50 years old. The researchers analyzed data spanning from 2004 to 2015 from the National Cancer Database.
They found that the proportion of patients under age 50 who were diagnosed with colorectal cancer under increased from 10% in 2004 to 12.2% in 2015. The researchers also found that doctors identified signs of advanced stages of the disease in over half of the diagnoses among younger adults.
Boone Goodgame, an assistant professor in the departments of internal medicine and oncology at the University of Texas-Austin and a senior author of the study, said, "[F]or practicing physicians, it feels like we are seeing more and more young people with colorectal cancer now than we were even 10 years ago."
What this means for adults under 50
The researchers said their findings were not surprising, but they reveal an alarming reality for young, U.S. adults.
Goodgame said researchers have yet to determine the cause of the uptick in colorectal cancer cases among younger adults, but it could be partly due to lifestyle choices. For instance, obesity, sedentary lifestyles, and diets low in fiber all are linked to colorectal cancer, as well as conditions such as chronic inflammation and Type 2 diabetes.
Rebecca Siegel, an epidemiologist at ACS, said while younger adults still face a lower risk of colorectal cancer when compared with older adults, the recent increase could indicate that millennials will face an elevated risk of the disease when they get older. "They'll carry that risk with them, so that they have a much higher risk than their parents when they reach their 50s and 60s," she said.
Groups update screening guidelines—but providers aren't following them, experts say
As colorectal cancer rates have continued to increase among young adults, more provider organizations are lowering their age recommendations for colorectal cancer screenings.
According to Goodgame, "just last year" many groups changed their guidelines to recommend colorectal cancer screening at age 45, down from age 50.
However, Goodgame said, "[M]ost physicians and patients don't appear to be following those recommendations."
Since colorectal cancer "is not on [physicians'] radar" when they treat younger patients, they usually do not send those patients for screenings until the disease has reached advanced stages, Siegel said.
Darren Brenner, a molecular cancer epidemiologist at the University of Calgary
, said the new guidelines also are not likely to encourage the detection or prevention of colorectal cancer among patients who are younger than 45. "We need to understand why this trend is occurring in young people in order to prevent it," he said (Sheikh, New York Times
, 7/31; Paddock, Medical News Today
, 7/22; AFP Relaxnews/Star2.com