An improved annual adenoma detection rate was associated with a significantly decreased risk of interval colorectal cancer (ICRC) and subsequent death in a national prospective cohort study published in the July issue of Gastroenterology (doi: 10.1053/j.gastro.2017.04.006).
This is the first study to show a significant inverse relationship between an improved annual adenoma detection rate (ADR) and ICRC or subsequent death, Michal F. Kaminski MD, PhD, of the Institute of Oncology, Warsaw, wrote with his associates.
The rates of these outcomes were lowest when endoscopists achieved and maintained ADRs above 24.6%, which supports the currently recommended performance target of 25% for a mixed male-female population, they reported ( Am J Gastroenterol. 2015;110:72-90 ).
This study included 294 endoscopists and 146,860 individuals who underwent screening colonoscopy as part of a national cancer prevention program in Poland between 2004 and 2008. Endoscopists received annual feedback based on quality benchmarks to spur improvements in colonoscopy performance, and all participated for at least 2 years. For each endoscopist, investigators categorized annual ADRs based on quintiles for the entire data set. “Improved ADR” was defined as keeping annual ADR within the highest quintile (above 24.6%) or as increasing annual ADR by at least one quintile, compared with baseline.
Based on this definition, 219 endoscopists (75%) improved their ADR during a median of 5.8 years of follow-up (interquartile range, 5-7.2 years). In all, 168 interval CRCs were diagnosed, of which 44 cases led to death. After age, sex, and family history of colorectal cancer were controlled for, patients whose endoscopists improved their ADRs were significantly less likely to develop (adjusted hazard ratio, 0.6; 95% confidence interval, 0.5-0.9; P = .006) or to die of interval CRC (95% CI, 0.3-0.95; P = .04) than were patients whose endoscopists did not improve their ADRs.
Maintaining ADR in the highest quintile (above 24.6%) throughout follow-up led to an even lower risk of interval CRC (HR, 0.3; 95% CI, 0.1-0.6; P = .003) and death (HR, 0.2; 95% CI, 0.1-0.6; P = .003), the researchers reported. In absolute numbers, that translated to a decrease from 25.3 interval CRCs per 100,000 person-years of follow-up to 7.1 cases when endoscopists eventually reached the highest ADR quintile or to 4.5 cases when they were in the highest quintile throughout follow-up. Rates of colonic perforation remained stable even though most endoscopists upped their ADRs.
Together, these findings “prove the causal relationship between endoscopists’ ADRs and the likelihood of being diagnosed with, or dying from, interval CRC,” the investigators concluded. The national cancer registry in Poland is thought to miss about 10% of cases, but the rate of missing cases was not thought to change over time, they noted. However, they also lacked data on colonoscope withdrawal times, and had no control group to definitively show that feedback based on benchmarking was responsible for improved ADRs.
Funders included the Foundation of Polish Science, the Innovative Economy Operational Programme, the Polish Foundation of Gastroenterology, the Polish Ministry of Health, and the Polish Ministry of Science and Higher Education. The investigators reported having no relevant conflicts of interest.