The Chile Biliary Longitudinal Study: A Gallstone Cohort.

Gallbladder cancer (GBC) is a highly fatal cancer that can be cured through cholecystectomy if identified early. The presence of gallstones is the primary risk factor for GBC, but few people with gallstones develop GBC. A key question is what drives the development of GBC among persons with gallstones. We initiated the Chile Biliary Longitudinal Study (Chile BiLS) to address this question. From 2016 to 2019, Chile BiLS enrolled 4,726 women aged 50-74 years with ultrasound-detected gallstones from southern-central Chile, accounting for an estimated 36% of eligible women with gallstones in the study area. The median age was 59 years; 25% of the women were Amerindian (Mapuche), 60% were obese, 25% had diabetes, and 6% had cardiovascular disease. Participants will be followed for gallbladder dysplasia or cancer for 6 years. As of April 30, 2020, over 91% of those eligible completed the year 2 follow-up visit. Data being collected include epidemiologic and sociodemographic information, anthropometric measurements, blood pressure, and tooth counts. Biosamples being taken include baseline plasma, buffy coat, red blood cells, serum, blood clot from serum, and PAXgene whole blood (PreAnalytiX GmbH, Hombrechtikon, Switzerland). Complete gallbladder sampling is conducted for most participants undergoing cholecystectomy. The Chile BiLS cohort study will increase our understanding of GBC etiology and could identify potential risk stratification and early detection strategies in high-risk areas.

Distribution of dysplasia and cancer in the gallbladder: an analysis from a high cancer-risk population.

Gallbladder dysplasia can progress to cancer and may be associated with increased cancer risk at other biliary tract sites. Thus, its accurate identification is relevant both for etiologic understanding and for clinical purposes. Data on the frequency and distribution of gallbladder dysplasia are lacking owing to limited gallbladder sampling and inability to visualize dysplasia grossly. An expert pathology group used consensus criteria to review 140 totally sampled consecutive cholecystectomy specimens from Chilean women. Three cases (2%) revealed incidental invasive carcinoma, all T2, along with high-grade dysplasia (HGD). The surface areas covered by dysplasia or cancer in these cases were 9%, 37%, and 87%. Although the first longitudinal ("diagnostic") section of the whole gallbladder captured HGD or cancer in all 3 cases, the deepest focus of invasive carcinoma was not present in this section. Fourteen additional cases (10%) had low-grade dysplasia (LGD), which was typically very focal (covering <5% of the surface) and most often occurred in the fundus. LGD was not present in the diagnostic section of 5 cases (38%) and would have been missed without additional sampling. None of the cancers or dysplasias were grossly visible. Although HGD and carcinoma are likely to be identified in "diagnostic" sections, accurate staging requires total sampling. LGD is typically very focal and would often be missed in routine practice. To identify cancer precursors, additional sampling, particularly of the fundus, may be warranted. The predominance of LGD in the fundus also provides etiologic insight, supporting the contribution of gallstones and chronic inflammation.