Utility of ancillary studies in the diagnosis and risk assessment of Barrett’s esophagus and dysplasia

www.nature.com/modpathol REVIEW ARTICLE OPEN Controversies in Pathology Utility of ancillary studies in the diagnosis and risk assessment of Barrett’s esophagus and dysplasia Won-Tak Choi 1✉ , Gregory Y. Lauwers2 and Elizabeth A. Montgomery3 1234567890();,: © The Author(s) 2022 Barrett’s esophagus (BE) is a major risk factor for the development of esophageal adenocarcinoma (EAC). BE patients undergo periodic endoscopic surveillance with biopsies to detect dysplasia and EAC, but this strategy is imperfect owing to sampling error and inconsistencies in the diagnosis and grading of dysplasia, which may result in an inaccurate diagnosis or risk assessment for progression to EAC. The desire for more accurate diagnosis and better risk stratification has prompted the investigation and development of potential biomarkers that might assist pathologists and clinicians in the management of BE patients, allowing more aggressive endoscopic surveillance and treatment options to be targeted to high-risk individuals, while avoiding frequent surveillance or unnecessary interventions in those at lower risk. It is known that progression of BE to dysplasia and EAC is accompanied by a host of genetic alterations, and that exploration of these markers could be potentially useful to diagnose/grade dysplasia and/or to risk stratify BE patients. Several biomarkers have shown promise in identifying early neoplastic transformation and thus may be useful adjuncts to histologic evaluation. This review provides an overview of some of the currently available biomarkers and assays, including p53 immunostaining, Wide Area Transepithelial Sampling with Three-Dimensional ComputerAssisted Analysis (WATS3D), TissueCypher, mutational load analysis (BarreGen), fluorescence in situ hybridization, and DNA content abnormalities as detected by DNA flow cytometry. Modern Pathology; https://doi.org/10.1038/s41379-022-01056-0 INTRODUCTION Barrett’s esophagus (BE) is a pre-neoplastic condition that is associated with an increased risk of developing dysplasia and esophageal adenocarcinoma (EAC)1–3. It is defined as endoscopically visible columnar epithelium containing goblet cells (intestinal metaplasia). Although the American Gastroenterological Association has not specified a length requirement1, the American College of Gastroenterology requires extension at least 1 cm proximal to the gastroesophageal junction4. BE is a genetically unstable metaplastic epithelium that accumulates an increasing number of genetic and chromosomal abnormalities as it progresses to low-grade dysplasia (LGD), high-grade dysplasia (HGD), and eventually EAC5–10. Because dysplasia is currently the primary clinical biomarker used to identify patients who are at an increased risk for EAC, clinical guidelines recommend that BE patients undergo periodic endoscopic surveillance with biopsies to detect dysplasia4. This allows for risk stratification and management of BE patients based upon the presence and grade of dysplasia prior to the development of EAC. The detection of HGD usually prompts endoscopic therapy, generally in the form of radiofrequency ablation (RFA) with or without endoscopic mucosal resection (EMR), due to its more frequent association with EAC compared with LGD11–16. However, a significant number of BE patients with dysplasia (~20%) are resistant to endoscopic therapy, and recurrences or progression to EAC during endoscopic therapy are not uncommon12,17–23. As for LGD, although continued surveillance every 12 months is an acceptable approach, there has been a shift toward endoscopic ablation therapy in recent years4,14–16,24–26. Subsequently, there is greater emphasis on optimization of the diagnosis of dysplasia as well as identification of patients who are more likely to progress to HGD/ EAC and/or have a poor response to endoscopic therapy. However, considering the annual cancer risk for patients with non-dysplastic BE (NDBE) is low (0.1–0.5% per year)27–29, identification of reliable biomarkers of low risk to allow prolongation of surveillance intervals compared with the current recommendations of repeating endoscopy every 3–5 years in those with NDBE4 remains an important goal of biomarker research. Even though endoscopic therapy has revolutionized the treatment of BE patients, the current surveillance protocols based on the histologic classification of BE have several shortcomings, including limited sampling of the affected BE segment (leading to false negative biopsy results), sampling error of potentially neoplastic lesions, and interobserver variability among pathologists in the diagnosis and grading of dysplasia, particularly for LGD30–35. In fact, there is evidence that the current surveillance 1 University of California at San Francisco, Department of Pathology, San Francisco, CA 94143, USA. 2H. Lee Moffitt Cancer Center and Research Institute, Department of Pathology, Tampa, FL 33612, USA. 3University of Miami Miller School of Medicine, Department of Pathology and Laboratory Medicine, Miami, FL 33136, USA. ✉email: Received: 15 December 2021 Revised: 9 February 2022 Accepted: 13 February 2022 W.-T. Choi et al. 2 protocols may not be effective in reducing mortality from EAC, with one study demonstrating that patients with fatal disease were nearly as likely to have received surveillance (55%) as were controls (60%)36. Furthermore, the rate of missed HGD/EAC (i.e., diagnosed within 1 year of negative endoscopy) is high (19–24%)37, suggesting that early repeat endoscopy, ideally within 1 year of an initial BE diagnosis, may be crucial, although the costeffectiveness of this approach remains to be determined. Notably, in a recent meta-analysis of 24 cohort studies of NDBE or LGD patients followed for at least 3 years after index endoscopy, Visrodia et al. reported that ~25% of EACs and 27% of HGD/EACs were classified as missed37. When only NDBE patients were considered, the rates of missed EACs and HGD/EACs were 24% and 19%, respectively37. Consequently, there is an increased interest in ancillary tests that could (1) improve the diagnostic accuracy of dysplasia (and its grading) in challenging situations to avoid a repeat endoscopic examination with biopsies (potentially more expensive than most ancillary tests); (2) predict which NDBE or LGD patients are at a higher risk for developing HGD/EAC (including missed lesions) so that such patients can be identified early and successfully treated with endoscopic therapy to prevent progression to EAC; (3) identify patients who are less likely to develop HGD/EAC so that the surveillance of low-risk patients can be reduced; and/or (4) predict those more likely to have a poor response to endoscopic therapy. In this regard, a variety of biomarkers and assays, such as p53 immunostaining38–42, Wide Area Transepithelial Sampling with Three-Dimensional Computer-Assisted Analysis (WATS3D)43–50, TissueCypher51–58, mutational load analysis (BarreGen)59–62, fluorescence in situ hyb (...truncated)