Detection rate of proximal serrated lesions: A new quality indicator for colonoscopy?

Serrated Polyps of Colon and Rectum: a Clinicopathologic Review

BACKGROUND

In the past decade, there have been significant changes in the classification and nomenclature of colorectal polyps. Previously, only two groups of lesions were widely recognized, the adenoma and the hyperplastic polyp. Adenomas were considered the only precursor of colorectal cancer, and hyperplastic polyps were considered innocent with no malignant potential. However, recent discoveries about molecular pathways of colorectal cancers have significantly changed our understanding of these neoplasms. Serrated polyps-previously uniformly called hyperplastic polyps-are now known to comprise a heterogeneous family of neoplasms united by their characteristic saw tooth morphology but differing in many important ways, including their malignant potential and molecular profile. This group of neoplasms includes both hyperplastic polyps and the more recently recognized serrated adenomas. Serrated adenomas can be subdivided into the traditional serrated adenoma and the sessile serrated adenoma/polyp. Both of these lesions show characteristic molecular changes, which differ from traditional colorectal adenomatous polyps.

OBJECTIVES

In this review, we will discuss the morphologic features of serrated colorectal lesions, the molecular alterations that characterize them, and their role in colorectal cancer development.

MATERIAL AND METHODS

The English literature regarding the new nomenclature will be reviewed and the key diagnostic points will be recorded.

RESULTS AND DISCUSSION

This large group of polyps has recently been better classified which needs specific attention by pathologists, gastroenterologists and even surgeons.

Carbon dioxide insufflation is associated with increased serrated polyp detection rate when compared to room air insufflation during screening colonoscopy

BACKGROUND AND STUDY AIMS

Sessile serrated adenomas (SSA) and traditional serrated adenomas (TSA) have been increasingly recognized as precursors of colorectal cancer. The aim of this study was to compare the effect of carbon dioxide insufflation (CO ₂ I) vs. room air insufflation (AI) on serrated polyp detection rate (SPDR) and to identify factors associated with SPDR.

PATIENTS AND METHODS

Single-center retrospective cohort study of 2083 screening colonoscopies performed with AI (November 2011 through January 2013) or CO ₂ I (February 2013 to June 2015). Data on demographics, procedure characteristics and histology results were obtained from a prospectively maintained endoscopy database and chart review. SPDR was defined as proportion of colonoscopies in which ≥ 1 SSA, TSA or hyperplastic polyp (HP) ≥ 10 mm in the right colon was detected. Multi-variate analysis (MVA) was performed to identify predictors of SPDR.

RESULTS

A total of 131 histologically confirmed serrated polyps (129 SSA, 2 TSA and 0 HP ≥ 10 mm) were detected. SPDR was higher with CO ₂ I vs. AI (4.8 % vs. 1.4 %; P  < 0.0001). On MVA, CO ₂ I was associated with higher SPDR when compared to AI (OR: 9.52; 95 % CI: 3.05 - 30.3). Both higher body mass index (OR 1.05; 95 % CI:1.02 - 1.09) and longer colonoscope withdrawal time (OR 1.11; 95 % CI: 1.07 - 1.16) were also associated with higher SPDR.

CONCLUSION

CO ₂ I is associated with higher SPDR when compared to AI during screening colonoscopy. While the mechanism remains unknown, we speculate that the favorable gas characteristics of CO ₂ compared to room air results in improved polyp detection by optimizing bowel insufflation. These findings suggest an additional reason to prefer the use of CO ₂ I over AI during colonoscopy.