TORONTO – Colorectal cancers are increasing sharply in the United States among young people, according to a study published Tuesday that suggests starting screening earlier than currently recommended.
Compared to those born around 1950, the risk of developing these cancers is the lowest, those born in the 1990s are twice as likely to develop colon cancer.
For rectal cancer, the risk is four times greater in this age group, also determined this study published in the Journal of the National Cancer Institute.
Other studies have already shown an increase in the incidence of colorectal cancers in those under 50 years of age, for whom regular screening is not generally recommended.
But these studies did not study the incidence of these cancers by age group for the younger ones, preventing to see the magnitude of this trend, explain the authors of the American Cancer Society.
The incidence of these cancers has been declining in the United States since the mid-1980s, thanks to the widespread use of screening at 50 years of age, thanks in particular to colonoscopy.
This explains why three out of ten colorectal cancers are now diagnosed in people under 55 years of age.
“Trends in young people are a bellwether for the future disease burden,” said Siegel. “Our finding that colorectal cancer risk for millennials has escalated back to the level of those born in the late 1800s is very sobering. Educational campaigns are needed to alert clinicians and the general public about this increase to help reduce delays in diagnosis, which are so prevalent in young people, but also to encourage healthier eating and more active lifestyles to try to reverse this trend.”
For this study, the researchers analyzed all colorectal cancers diagnosed from the age of 20 years between 1974 and 2013 in national epidemiological studies, totaling 490,305 cases.
After a decline in the incidence of colon cancer from 1974, the curve has reversed with an increase of 1% to 2% per year since the 1980s in adults aged 20 to 39 years and 0.5 % To 1% among those aged 40 to 54 from the mid-1990s.
The incidence of rectal cancer increased more strongly and more rapidly than colon cancer with an increase of about 3% annually from 1974 to 2013 among 20-29 year olds and from 1980 to 2013 among 30-39 year olds.
In the 40-54 age group, the rate of this cancer has increased by 2% per year since the 1990s.
By comparison, rectal cancer has been declining in people aged 55 and over for at least the last forty years.
The authors, including Rebecca Siegel of the American Cancer Society, encourage healthier eating habits and physical activity to try to reverse this trend and suggest starting screening at a younger age.