A quantitative assessment of the risks and cost savings of forgoing histologic examination of diminutive polyps

Background and aims: Endoscopic prediction of polyp histology is rapidly improving to the point where it may not be necessary to submit all polyps for formal histologic assessment. This study aimed to quantify the expected costs and outcomes of removing diminutive polyps without subsequent pathologic assessment. Methods: Cross-sectional analysis of a colonoscopy database for polyp histology; decision models that quantify effects on guideline-recommended surveillance and subsequent costs and consequences. The database was composed of consecutive colonoscopies from 1999 to 2004 at a single-institution tertiary care center. Patients were those found to have at least one diminutive polyp removed during colonoscopy, irrespective of indication. The main outcome measurements include up-front cost savings resulting from forgoing pathologic assessment; frequency and cost of incorrect surveillance intervals based on errors in histologic assessment; number needed to harm (NNH) for perforation and/or interval cancer. Results: Incorrect surveillance intervals were recommended in 1.9% of cases when tissue was submitted for pathologic assessment and 11.8% of cases when it was not. Based on the annual volume of colonoscopy in the US, the annual up-front cost savings of forgoing the pathologic assessment would exceed a billion dollars. An upper estimate on the downstream costs and consequences of forgoing pathology suggests that less than 10% of the up-front savings would be offset and the NNH exceeds 11000. Conclusion: Endoscopic diagnosis of polyp histology during colonoscopy and forgoing pathologic examination would result in substantial up-front cost savings. Downstream consequences of the resulting incorrect surveillance intervals appear to be negligible.