Rate and Predictors of Reclassification of Previously Diagnosed Hyperplastic Polyps to Sessile Serrated Adenomas in a City Wide Practice. Implications for Polyp Surveillance Recommendations

Abstract

Purpose: We evaluated the reclassification rate of recently diagnosed hyperplastic polyps (HP) to sessile serrated adenomas (SSAs) and the predictors of such reclassification. Methods: The provincial pathology database was searched for all colon polyps reported in the six pathology laboratories in the entire city in 2009. All retrieved pathological 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 gastrointestinal pathology. Polyp size, colonic location, age and sex of the study subjects were evaluated as potential predictors of reclassification. Results: 4,096 pathology reports by 25 different pathologists were reviewed. 20% of the polyps were reported as serrated colon polyps (SCPs). 17% 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 colon [OR: 4.7; 95% CI: 1.4-15.4] were independent predictors of reclassification. 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.