Improved Adenoma Detection Linked With Lower CRC Death Risk

June 17, 2015

Using simulation modeling, researchers found that higher adenoma detection rates were linked with lower lifetime colorectal cancer incidence and mortality.

Using simulation modeling, researchers have found that higher quality colorectal cancer screening, as measured by adenoma detection rates, was associated with a lower lifetime risk for colorectal cancer incidence and mortality.

Results of the study were published in JAMA.

“Our results suggest that higher adenoma detection rates may be associated with up to 50% to 60% lower lifetime colorectal cancer incidence and mortality without higher net screening costs despite higher number of colonoscopies and polypectomy-associated complications,” wrote study author Reinier G. S. Meester, MSc, of Erasmus MC University Medical Center, Rotterdam, the Netherlands, and colleagues.

According to the study, adenoma detection rate, or the proportion of a physician’s screening colonoscopies that detect at least one histologically confirmed adenoma, has been found to have great variation across physicians in the United States. “Future research is needed to assess why adenoma detection rates vary and whether increasing adenoma detection would be associated with improved patient outcomes,” wrote the authors.

In this modeling study, Meester and colleagues evaluated colorectal cancer screening outcomes by different adenoma detection rate levels. They compared no screening with screening with colonoscopy according to adenoma detection rates quintiles: (averages 15.3%, quintile 1; 21.3%, quintile 2; 25.6%, quintile 3; 30.9%, quintile 4; and 38.7%, quintile 5).

The model showed that unscreened patients had a 34.2 per 1,000 lifetime risk for colorectal cancer occurrence and a mortality risk of 13.4 per 1,000. In patients who underwent screening, the lifetime incidence of and mortality from colorectal cancer was tied to the rates of adenoma detection. Specifically, patients in quintile 1 had a mean lifetime incidence of 26.6 per 1,000 compared with 12.5 per 1,000 for patients in quintile 5, and a mean mortality rate of 5.7 per 1,000 for quintile 1 compared with 2.3 per 1,000 for quintile 5.

The model estimated that lifetime incidence and mortality risks averaged 11% to 13% lower for every five-point higher adenoma detection rate, which translates to overall differences of 53% to 60% between the lowest and highest quintiles.

The researchers also used their model to estimate complications for colonoscopy. The rate of complications increased from 6 of 2,777 in quintile 1 to 8.9 of 3,376 in quintile 5, which the researchers wrote was related to “more frequent surveillance in patients of physicians with higher adenoma detection rates.”

Finally, the combined costs of screening and treatment in quintile 1 were $5.2 million compared with $4.9 million in quintile 5. The estimated net screening costs were therefore lower in quintile 5 compared with quintile 1 ($1.8 million vs $2.1 million), due to the estimated costs of cancer treatment that would be avoided.

“Our findings for the average association between adenoma detection rates and patient outcomes do not necessarily mean that modifying adenoma detection rates alone in individual physicians would lead to fewer interval cancers for their patients,” the researchers cautioned, “given that modeling cannot prove causal relationships.”