Improving Colonoscopy Quality for Colorectal Cancer Screening in the National VA Healthcare System

Colorectal cancer (CRC) prevention is a top VA priority. Veterans are highly impacted by CRC, the third most common cancer diagnosed with a 3-year mortality rate of 35%. Colonoscopy screening can save lives, and is the cornerstone of effective prevention. The National Polyp Study showed that removal of adenomas during screening colonoscopy decreases the subsequent development of CRC by up to 90% and death by up to 50% in comparison to historical controls. In VA, colonoscopy is the primary CRC screening modality with over 200,000 colonoscopies performed each year. Eighty-two percent of Veterans are up-to-date on CRC screening, with 89% having a colonoscopy. However, the quality of those VA colonoscopies is unknown.

High quality colonoscopy is critical for CRC prevention. Observational studies found significant rates of CRC even after normal colonoscopy, likely due to colonoscopists' varied performance in detecting and removing polyps. Among Medicare beneficiaries, approximately 7% of all CRC occurred in individuals who had colonoscopy that apparently missed the CRC diagnosis. A pooled analysis from eight surveillance studies suggested 52% of incident CRCs after colonoscopy were due to missed lesions. These interval cancers highlight the need to focus on colonoscopy quality indicators.

Adenoma detection rate (ADR) significantly varies by provider and has been strongly linked to both CRC incidence and mortality. In essence, polyps that are not found cannot be removed for CRC prevention. ADR, defined as the proportion of screening colonoscopies performed by a physician that has one or more histologically-confirmed adenomatous polyps or CRC, is the primary benchmark for colonoscopy inspection quality. Increasing ADR correlates with a lower risk of interval and fatal CRC. A landmark US study of 314,872 colonoscopy exams showed marked variability in providers' ability to detect polyps, with the ADR ranging from 7.4 to 52.5%. In patients of providers with the highest ADRs, as compared with those in the lowest, the adjusted hazard ratios (HR) for fatal interval CRC was 0.38 (95% Confidence Interval [CI], 0.22 to 0.65). Each 1% increase in ADR was associated with a decrease risk of 3% for interval CRC and 5% for CRC death.

Using the methods the team developed, the investigators have powerful pilot results showing colonoscopy quality variability in the VA and direct association with CRC death. From 1999-2011, there were 634,331 Veterans with baseline colonoscopy performed by one of 3101 colonoscopists with ADRs ranging from 13-79%. In patients who had a colonoscopy without polyps found, the higher the provider ADR, the more protected the patient was from developing future CRC: adjusted HR (adjHR) 0.57 for incident (95%CI: 0.42-0.79; ptrend< 0.001) and 0.73 for fatal (95%CI: 0.50-1.06; p=0.047) CRC for the highest vs. lowest ADR quintile. Among individuals who had a colonoscopy with polypectomy, increasing ADR was also associated with reduced risk: adjHRs 0.46 for incident (95%CI: 0.34-0.62; ptrend< 0.001) and 0.53 for fatal (95%CI: 0.34-0.84; ptrend=0.006) CRC for the highest vs. lowest quintile. A 5% absolute increase in ADR was associated with relative reductions in fatal CRC risk of 4% after normal colonoscopy (adjHR 0.96, 95%CI: 0.95-0.97) and 6% after polypectomy (adjHR 0.94; 95%CI: 0.89-0.98) Other important quality metrics, including bowel preparation quality and cecal intubation rate also impact patient outcomes with poor bowel preparation and incomplete examinations associated with missed lesions and need for earlier repeat procedures.

Audit and feedback of colonoscopy quality improves performance and outcomes. The VA Surgical Quality Improvement Program (VASQIP) is an example of a VA nationwide reporting system that formed to focus on quality and has led to a decrease in mortality of 47% in patients 30 days after surgery. VASQIP provides information to providers for self-assessment and quality improvement purposes. There is similarly strong evidence that providing colonoscopy performance feedback improves quality and patient outcomes. Kahi and colleagues showed in a single-center VA setting that a quarterly report card improved colonoscopy quality. Most recently, in a large prospective European cohort study evaluating annual feedback and quality benchmark indicators on screening colonoscopy performance, the majority of the endoscopists (74.5%) increased their annual ADR. Moreover, individuals examined by endoscopists in the highest ADR quintile (> 24.6%) had significantly lower risk of interval CRC and death. When compared with no increase in ADR, reaching or maintaining the highest quintile ADR decreased adjusted hazard ratios for interval and fatal CRC to 0.27 (95% CI, 0.12-0.63; p = .03), and 0.18 (95% CI, 0.06-0.56; p = .03).