Pathological reassessment of hyperplastic colon polyps in a city-wide pathology practice: implications for polyp surveillance recommendations

Background Sessile serrated adenomas (SSAs) and hyperplastic polyps (HP) are the two most common types of serrated colon polyps (SCPs). SSAs are suspected to be the precursor lesions for many colorectal cancers, and hence there is an emphasis on their detection and removal. On the other hand, recent guidelines such as those from the European Union consider HPs of limited clinical significance. Objective Evaluate the reclassification rate of recently diagnosed HPs to SSAs and the predictors of such reclassification. Design, Setting, Intervention, Main Outcome Measurements The provincial pathology database was searched for all colon polyps reported in the 6 pathology laboratories in the city of Winnipeg in 2009. All retrieved pathology slides for previously reported right-sided HPs and a 20% random sample of left-sided HPs were reassessed by two pathologists with a special interest in GI pathology. Polyp size, colon location, and age and sex of the study participants were evaluated as potential predictors of reclassification. Results A total of 4096 pathology reports by 25 different pathologists were reviewed. Twenty percent of the polyps were reported as SCPs. Seventeen percent of right-sided previously reported HPs and 20% of those >5 mm were reclassified as SSAs. Size >5 mm (odds ratio [OR] 4.2; 95% confidence interval [CI], 1.5-11.4) and location in the right side of the colon (OR 4.7; 95% CI, 1.4-15.4) were independent predictors of reclassification. Limitations Retrospective review. Conclusion A significant proportion of recently reported right-sided HPs may be SSAs. Surveillance recommendations for SCPs should consider the size and location of SCPs and not just the reported type.