Sessile Serrated Adenoma/Polyp (SSA/P) Detection Rate Comparing Screening and Surveillance Colonoscopy

Abstract

Introduction: The adenoma detection rate (ADR) is recognized as an important quality measure for colonoscopy. The emerging appreciation of the role of the serrated pathway in colorectal neoplasia makes serrated polyp detection rate (SDR) another potential indicator of quality colonoscopy. We aim to provide data about SDR in different indications for colonoscopy at our institution. Methods: We performed a retrospective chart review of consecutive outpatient colonoscopies before and after implementation of split dose bowel preparation (split prep). We included complete colonoscopies with adequate bowel preparation performed on outpatients by academic gastroenterologists at a single VA medical center. The indications for colonoscopy included colorectal cancer screening, surveillance of polyps, FIT/FOBT positivity, IBD, and others. SDR was defined as the proportion of cases with at least one SSA/P. Collected data included patient demographics, procedural indication, and presence, number, size, histology, and anatomic location of polyps. JMP 13.1.0 was used for analysis. Results: 1100 patients were included. 93% were males with 50% African Americans and 49% Caucasians. Procedural indications included polyp surveillance (39%), screening (19.82%), FIT/FOBT positivity (17.82%), IBD (3.18%), and others (20.18%). ADR was highest in the FIT/FOBT positive group (72.96%), followed by surveillance colonoscopy (71.79%), screening group (53.21%), others (41.44%) and IBD (11.43%). The highest SDR was in the colorectal cancer screening group (16.51%), followed by polyp surveillance (11.42%), FIT/FOBT positivity (9.69%), IBD (8.57%), and others (6.31%). There was a non-statistically significant trend towards increased SDR in both screening and surveillance groups with implementation of split prep (screening 14.53% vs. 18.81%, P=0.40; surveillance 10.76% vs. 12.14%, P=0.66). Limitations: Retrospective design, single VA medical center, sample size, and very elevated ADR and SDR rates. Conclusion: Our results support current literature that ADR is significantly higher in surveillance colonoscopy for history of adenomas, as compared to screening colonoscopy. However, the rates of detection of SSA/P were not very different when comparing screening and surveillance groups, with a trend towards higher rates in screening cases (P=0.07) (Table 1), suggesting different risk factors for this neoplastic pathway.Table: Table. ADR and SDR in Screening and Surveillance Colonoscopies