P-L04 Temporal changes in prevalence and associated risk factors for gallbladder dysplasia and adenocarcinoma in patients undergoing cholecystectomy. A UK hospital-based observational study

Background A metaplasia-dysplasia–carcinoma sequence is the most plausible carcinogenic pathway for gallbladder cancer. Although the incidence of gallbladder carcinoma is increasing, little is known about its precancerous lesions. The aim of this study was to determine temporal changes in the prevalence of low-grade dysplasia (LGD), high-grade dysplasia (HGD) and gallbladder adenocarcinoma and associated risk factors. Methods We retrospectively identified consecutive patients who underwent cholecystectomy between January 2011 and March 2020. Patients were grouped according to histology: no dysplasia; LGD; HGD; and adenocarcinoma. Fitted linear models estimated temporal trends in prevalence and mean age for all histological outcomes. Logistic regression estimated associated risk factors. Results A total of 5 835 patients were included in the analysis. The prevalence of LGD was 1.47%, HGD 0.17% and adenocarcinoma 0.19%. Prevalence for all diseases increased over time, and mean age at diagnoses decreased over time. In a multivariate logistic regression model, with no dysplasia as the reference group, female sex increased the odds of LGD (OR 4.57, 95% CI 3.07-10.10, p = <0.0001).  BMI was not associated with disease risk. Conclusions Our data suggests the prevalence of precancerous gallbladder lesions are increasing in younger patients. Although a risk factor for cholelithiasis, BMI was not associated with disease progression.  If occurring in a dysplasia-carcinoma sequence, mean age of diagnoses suggests a progression period of 20 years. Further research is required to explain both the significant sex disparity and potential environmental risk factors for gallbladder dysplasia.