# A89 PREVALENCE AND OUTCOMES OF SERRATED POLYPOSIS SYNDROME IN TERTIARY GASTROENTEROLOGY PRACTICES: A RETROSPECTIVE ANALYSIS

## TL;DR

This study found that 3% of patients with at least one serrated lesion had Serrated Polyposis Syndrome, and most were diagnosed by gastroenterologists after multiple colonoscopies.

## Contribution

The study provides real-world data on SPS prevalence and outcomes in a tertiary gastroenterology setting.

## Key findings

- The prevalence of SPS among patients with at least one SSL was 3%.
- Most SPS diagnoses were made after a median of 3 colonoscopies and 3 years of follow-up.
- 74% of SPS cases were diagnosed by the primary gastroenterologist.

## Abstract

While serrated polyposis syndrome (SPS) is associated with an increased risk of colorectal cancer (CRC), incident CRC can be mitigated through programmatic endoscopic surveillance. Diagnosing SPS remains challenging due to physician awareness and the logistics of cumulative polyp tracking. There is a lack of data on SPS prevalence and outcomes outside of established cohorts.

To evaluate the prevalence and outcomes of SPS within tertiary gastroenterology practices.

Using a validated histopathology database, all patients with at least 1 sessile serrated lesion (SSL) removed by 1 of 11 gastroenterologists in a tertiary centre between 2013-2023 were considered for evaluation. All patients were subsequently screened for SPS based on the 2019 World Health Organization (WHO) criteria. Patients meeting SPS criteria underwent full chart review for demographic, procedural, and clinical outcomes. Analysis was based on serrated class lesions (SCLs), which included sessile serrated lesions, hyperplastic polyps, and traditional serrated adenomas.

A total of 6117 patients had at least 1 SSL of which 178 (3%) met SPS criteria (110 WHO I, 10 WHO II, 58 WHO I/II). Median age at first colonoscopy was 62 years (IQR 54-71 years) and 115 (65%) were female. Diagnostic criteria were achieved over a median of 3 years (IQR 1-9 years) and a median of 3 colonoscopies (IQR 2-4 colonoscopies). On index colonoscopy, patients eventually meeting SPS criteria had a median of 3 SCLs (IQR 2-6 SCLs) with median largest lesion size of 11mm (IQR 5-18mm) whereas patients without SPS had a median of 1 SCL (IQR 1-2 SCLs) with median largest lesion size of 5mm (IQR 4-8mm) (p<0.001). SPS was diagnosed by the gastroenterologist in only 132 (74%) patients. SPS was managed by endoscopy and surgery in 157 (88%) and 21 (12%) respectively. Reasons for surgery included polyp burden (9, 5%), endoscopic adverse event (1, 0.5%) and CRC (11, 6%). CRC was diagnosed either before or concurrent to SPS diagnosis in 7 (63.6%).

In patients with at least 1 SSL, the prevalence of SPS was 3% and the diagnosis was recognized in 74% by the primary gastroenterologist. Increased awareness of SPS criteria alongside consideration for modified surveillance intervals based on index SCL size and number may improve patient outcomes.

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