Prevalence of advanced polyps similar at ages 45-49, 50-54 years
SAN ANTONIO — The increased prevalence of advanced adenoma and clinically significant serrated polyps was similar among age groups on both sides of age 50 years, suggesting that screening at 45 years optimizes colorectal cancer prevention, according to study results presented at the American College of Gastroenterology Annual Meeting.
Lynn F. Butterly, MD, of Dartmouth-Hitchcock Medical Center, said that while the incidence of CRC among patients older than 50 years has decreased significantly, it has increased by more than 50% among patients younger than 50 years.
“In May of 2018, the [American Cancer Society] made a qualifying recommendation to lower the age to start colorectal cancer screening to 45 from 50, where it is now,” she said in her presentation. “The authors note that the qualified recommendation indicates that there is clear evidence of benefit, just less certainty about the balance of benefits and harms and patient preferences due to lack of hard available data.”
Researchers analyzed data from the New Hampshire Colonoscopy Registry to explore age-related prevalence of advanced findings among an average risk screening cohort comprising individuals aged younger than 50 years compared with older patients. To ensure they had the appropriate average risk population, investigators excluded higher-risk indications like gastrointestinal bleeding, occult blood, iron deficiency anemia and abnormal imaging. They also excluded surveillance exams, individuals with family history of CRC, incomplete exams and exams with poor bowel preparation. Patients with symptoms like abdominal pain and constipation were included as an “average risk equivalent” cohort.
Among their study population (n = 43,600), Butterly and colleagues found that advanced adenoma prevalence increased significantly at age 40 years, and the prevalence at ages 45 to 49 was similar to that found in ages 50 to 55 (3.7% vs. 3.6%).
Prevalence of advanced adenomas was 4.4% at screening, 3.2% in the included diagnoses and 5.8% in the excluded diagnoses, which Butterly said supported their assumptions about indication. Additionally, low-risk symptoms were not associated with an increased risk (OR = 1.03; 95% CI, 0.84–1.13).
“The clinical implications of our findings are that our findings support the recommendation to begin average risk colorectal cancer screening at 45,” Butterly said. “Clearly, future research will need to address risk stratification within that 45- to 49-year-old group, as well as effectiveness and cost effectiveness of the various screening options.” – by Alex Young
Reference:
Butterly LF, et al. Abstract 25. Presented at: American College of Gastroenterology Annual Meeting; Oct. 25-30, 2019; San Antonio.
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