Lowering of CRC-Screening Age Likely to Affect Colonoscopy Demand, Case Mix, Adenoma Detection

By Reuters Staff

December 07, 2021

NEW YORK (Reuters Health) - The recent lowering of colorectal cancer (CRC)-screening age from 50 to 45 years is likely to affect demand for colonoscopy and case mix, and result in a modest lowering of adenoma-detection rate (ADR), the chief colonoscopy-quality metric, a new analysis suggests.

Dr. Seth Crockett of the University of North Carolina at Chapel Hill and Dr. Uri Ladabaum of Stanford University in California modeled scenarios reflecting, a base case (before the age eligibility change), a future steady state of screening participation based on age and a temporary high influx ("bolus") of 45-49-year-old screenees.

In the base case cohort of 1,000 screenees, 34.8% were 50 to 54 years old, 18.1% were 55 to 69, 19.2% were 60 to 64 and 14.3% were 65 to 69. In the future steady-state scenario, the cohort size increased to 1,159, and the largest age stratum shifted to the newly screen-eligible 45-to-49 age group (30.0%).

In the "bolus" scenario, assuming a doubling of 45-49 year-old screenees, the cohort size increased to 1,507 (with 46.2% aged 45-49). In the "bolus" scenario assuming a five-fold increase in 45-49-year-old screenees, the cohort size increased to 2,550 (with 68.2% aged 45-49).

"The bolus scenarios illustrate the possible challenges of accommodating large numbers of newly-eligible 45-49 year-old screenees in the short term," the researchers write in Gastroenterology.

"Noninvasive screening with fecal immunochemical testing (FIT) and emerging blood tests, and prioritization of colonoscopy for higher-risk patients, could mitigate the challenges of expanding the screen-eligible population," they suggest.

The researchers also examined the potential impact of lowering CRC screening age on individual endoscopists' ADR.

"Our results demonstrate how the new screening initiation age could lead endoscopists with currently borderline ADRs to fall below the 25% threshold. This group represents roughly one-fifth to one-fourth of the endoscopy workforce," Dr. Crockett and Dr. Ladabaum report.

"For endoscopists with higher current ADRs, even a large surge of younger screenees is unlikely to shift them below the performance threshold. This raises challenging questions. Should ADR calculations include 45-49 year-olds? Should ADR thresholds be adjusted?"

"We believe 45-49 year-olds must be included in ADR measurement without adjusting ADR thresholds, and we encourage non-invasive screening and optimal allocation of colonoscopies in settings with constrained resources," they conclude.

They caution that they did not model potential increased utilization of FIT or emerging blood-based biomarkers, which could affect screening colonoscopy demand.

SOURCE: https://bit.ly/3IgoIGQ Gastroenterology, online November 25, 2021.

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