Colorectal cancer rates rising dramatically in young adults
Adults born in 1990 are twice as likely to be diagnosed with colon cancer and four times as likely to be diagnosed with rectal cancer as people born in 1950, according to a retrospective analysis published in Journal of the National Cancer Institute.
Further, three in 10 rectal cancer diagnoses are now made in patients aged younger than 55 years.
“Causes for the rise in colorectal cancer (CRC) are unknown,” Rebecca L. Siegel, MPH, director of surveillance information in the Surveillance and Health Services Research Program at the American Cancer Society, told HemOnc Today. “Our finding that CRC risk for millennials has escalated back to the level of those born in the late 1800s is very sobering.”
“We hypothesize that some of the factors known to increase CRC risk, including excess body weight; sedentary behavior; high consumption of red/processed meat; and low consumption of fruits, vegetables, and dairy products (calcium) have probably contributed to the increase,” Siegel added. “Notably, the rise in CRC parallels the obesity epidemic, which implicates those behaviors thought to have driven the high obesity rates, like being less physically active and eating less healthy.”
Educational campaigns are needed to alert clinicians and the general public about the rise in CRC incidence and the importance of healthier eating and more active lifestyles to try to reverse the trend.
Overall, CRC incidence rates have been declining in the United States since the mid-1980s, with steeper drops in the past decade driven by increased screening. However, recent studies have reported increased CRC incidence in adults aged younger than 50 years, for whom screening is not recommended.
Still, these studies have not examined the temporal trend simultaneously by age, calendar period and year of birth.
To characterize trends in population-based CRC occurrence by tumor location, age at diagnosis, and year of birth, researchers used age-period-cohort modeling, a quantitative tool designed to disentangle factors that influence all ages — such as changes in medical practice — from factors that vary by generation, typically due to behavioral changes.