PURPOSE

Colorectal cancer (CRC) screening is effective in finding early stage CRC and dramatically improves survival rates. Despite this, the number of eligible patients who do not obtain CRC screening is unacceptably high.

METHODS

We conducted a longitudinal, randomized controlled trial investigating the utility of a blood-based protein assay on the quality of care delivered by practicing PCPs in the United States. We used standardized simulated patients (CPVs), presenting with symptoms suggestive of a higher likelihood of CRC, to measure how frequently these PCPs ordered diagnostic colonoscopy. 190 PCPs cared for three patients at baseline and three patients post-intervention. The PCPs were randomized into one of two study arms: control and intervention. The intervention arm consisted of educational materials about the blood-based protein assay and positive test results. Each simulated patient in the intervention arm had a positive test result that was given to the doctor. The controls were given neither intervention materials nor blood-based protein assay results. Physician responses in both groups were scored against evidence-based criteria. Data were collected at baseline and post-intervention.

RESULTS

At baseline, we found that 71% of physicians ordered diagnostic colonoscopy. In round 2, 23% of physicians in the intervention arm adopted the new blood-based protein assay. Ordering physicians were 3.88 (95% CI 1.67-9.03) times more likely to order a diagnostic colonoscopy. In percentage terms, those who ordered the assay were more likely to order colonoscopy (92%) than either intervention physicians who did not order the assay (77%) or control physicians (66%) (p < 0.001). A marginal effects estimation showed that use of the assay would increase ordering colonoscopy to nearly 95%.

CONCLUSION

Over one-third of adults in the United States do not follow the recommended screening guidelines for CRC. The introduction of a blood-based protein assay significantly increased the likelihood that physicians would order diagnostic colonoscopies in elevated-risk patients compared to those without access to the assay results. The overall change in clinical utility observed here has the potential to significantly improve clinical care.