O42 Incidence of dysplasia in fundic gland polyps: a retrospective cohort study

Field: Medicine (Health Sciences)

Introduction

Fundic gland polyps are the most frequently encountered type of gastric polyp (13–77%),1 2 and, whilst they are typically <1cm, those >1cm carry both a reported dysplasia rate and focal cancer rate of 1.9%; therefore, it has been suggested that fundic gland polyps >1cm should be resected or undergo targeted biopsy,3 which consequently generates a considerable amount of work for endoscopy services as well as histopathology departments, from targeted biopsies alone. This study looks to evaluate the frequency of neoplastic change within fundic gland polyps (FGPs) – specifically, it aims to establish the approximate dysplasia rate of all biopsies from these lesions.

Methods

This was a single-centre, retrospective, cohort study performed using patient records from October 2007 to October 2022. Individuals aged ≥18 years who underwent biopsy of confirmed FGPs were included, with the histological confirmation of a FGP based on the report of an expert histopathologist (as the presence of dysplasia, or adenocarcinoma). Patients with hereditary polyposis syndromes were excluded. Endoscopic data (FGP size, if recorded, and method of endoscopic resection, where performed), were collected from electronic gastroscopy reports. Histologic data (dysplasia with grade, and neoplasia with type) were obtained from the pathology report.

Results

Of the 1384 biopsies of histologically-confirmed fundic gland polyps analysed, 13 (0.94%) had unequivocal low-grade dysplasia, and 2 (0.14%) had unambiguous high-grade dysplasia, with these figures only modestly increasing to 17 (1.23%) and 3 (0.22%), respectively, with inclusion of specimens that were indefinite for dysplasia. This suggests an overall (with inclusion of high- and low-grade) dysplasia rate on biopsy of FGPs of between 1.08% and 1.45%. of the dysplastic polyps, 87% were low grade. Whilst a great deal of descriptive data was missing from endoscopy reports, from the data available, the size range of the aforementioned biopsied polyps was 1–30mm, with a median of 5mm. And, once gain acknowledging the incompleteness of the data in terms of endoscopic measurements, pooling both biopsy and polypectomy cases revealed the median size of FGPs with dysplasia was 8mm, whilst that of FGPs without dysplasia was only 5mm in our data-set. Over the entire 15-year study period, not a single biopsy returned evidence of established gastric adenocarcinoma or neoplasia of any kind.

Conclusion

The overall dysplasia rate of FGPs is consistent with what is stated in previous literature of <2%. of the dysplasia seen, the vast majority is low-grade – it represented 87% of the dysplasia identified from our biopsies. The progression rate from low grade dysplasia to cancer is questionable given the low rate of high-grade dysplasia and negligible cancer rate in these from our series of over 1000 biopsies. The existence of demographic (age, sex etc.) predictors of non-polyposis dysplasia remains to be established, though represents an interesting avenue for exploration in future publications.

References

Carmack SW, Genta RM, Graham DY, et al. Management of gastric polyps: a pathology-based guide for gastroenterologists. Nat Rev Gastroenterol Hepatol 2009;6:331–41. Evans JA, Chandrasekhara V, Chathadi KV, et al. The role of endoscopy in the management of premalignant and malignant conditions of the stomach. Gastrointest Endosc 2015;82:1–8. Banks M, Graham D, Jansen M, Gotoda T, Coda S, di Pietro M, Uedo N, Bhandari P, Pritchard DM, Kuipers EJ, Rodriguez-Justo M, Novelli MR, Ragunath K, Shepherd N, Dinis-Ribeiro M. British Society of Gastroenterology guidelines on the diagnosis and management of patients at risk of gastric adenocarcinoma. Gut 2019 Sep;68(9):1545–1575. doi: 10.1136/gutjnl-2018-318126. Epub 2019 Jul 5. PMID: 31278206; PMCID: PMC6709778.