Largest Study to Date Supports CRC Screening Before Age 50
"We found that 5% of average-risk persons aged 45-49 years
had advanced neoplasia and 28% had adenoma, which supports lowering the
screening age to 45 years and maintaining the current adenoma detection
benchmarks
The adenoma prevalence, or adenoma detection rate (ADR), in
average-risk adults younger than age 50 was 23.5% in women, 34.4% in men, and
28.3% overall, which implies that the current ADR benchmarks of 20% for women,
30% for men, and 25% overall could be maintained for younger screening
participants, Liang and colleagues say.
The study was published May 25 in the journal Gastroenterology.
Benefit Before Age 50
Confirmed
The prevalence of advanced neoplasia and adenomas among
average-risk adults younger than age 50 has not been well characterized.
This study provides "the most accurate estimate of
neoplasia prevalence in individuals aged 45-49 years — who are newly joining
the screening pool — as well as other individuals across the age
spectrum," Liang told Medscape Medical News.
Using a large US endoscopy registry, the researchers calculated
age-stratified prevalence and predictors of colonic neoplasia based on more
than 3.9 million screening colonoscopies, of which 3.3% were performed in
average-risk adults younger than age 50.
The prevalence of advanced neoplasia and adenomas in 45-49
year-olds was 5% and 28.3%, respectively. In 50-54 year-olds, the prevalence
was 6.2% and 33%, respectively.
Among 45-49 year-olds, the rates of advanced neoplasia and
adenomas were higher in men (6.2% and 34.4%, respectively) than women (4.1% and
23.5%, respectively).
Men had a higher prevalence of neoplasia than women for every
age group studied, and the prevalence of advanced neoplasia in average-risk men
aged 45-49 years was comparable to that of women aged 65-69 years (6.2% and
6.4%, respectively).
In adults younger than age 50, predictors of advanced neoplasia
on multivariable logistic regression included older age, male sex, family
history of colorectal cancer (CRC) or advanced adenomas, and obesity.
By race, White adults had a higher prevalence of advanced
neoplasia than Black, Hispanic, and Asian individuals across the age spectrum,
which was partially driven by serrated lesions.
Overall, the findings support starting CRC screening at age 45
years, "which will likely result in a level of protection against CRC in
this younger age group that is clinically comparable to the 50-54 year age
group," Liang and colleagues write.
Weighing in on the findings, Andrew T. Chan, MD, MPH, a
gastroenterologist and professor of medicine at Massachusetts General Hospital
and Harvard Medical School in Boston, said the study shows that adults aged
45-49 years have a fairly "comparable prevalence of polyps at higher risk
of becoming colorectal cancer to adults aged 50-59 years."
He noted that recent data, including a study from his group
reported previously by Medscape Medical News, also
showed that starting screening at an earlier age resulted in substantial benefits
to younger individuals.
"Taken together, these studies support recent
recommendations to lower the age of initiation of screening to age 45,"
Chan said.
"There remains a need for data to understand the
acceptability and uptake of screening among younger individuals, including
comparisons of more noninvasive screening modalities, such as stool-based
testing, with colonoscopy," he said.