Variable pathologic interpretation of columnar lined esophagus by general pathologists in community practice

Cytology in Barrett's esophagus

Brush cytology is complementary to endoscopic biopsy and is recommended by some to be part of the routine endoscopic surveillance of patients with BE. Advantages of cytology include the ability to sample a greater area of involved epithelium, preferential exfoliation of the less cohesive dysplastic cells, simplicity, and lower cost. There are clear cytologic criteria for dysplasia, and biomarker studies can be performed on cytologic specimens. Despite these advantages, cytology is used by only 17% of gastroenterologists in the United States today. Limited data are available on the usefulness of cytology in the diagnosis and surveillance of BE. Cytology has good sensitivity for the detection of adenocarcinoma and HGD and good specificity for the detection of IM without dysplasia. Furthermore, cytology may detect abnormalities missed by biopsy. Cytology has problems in the detection of LGD, however. For cytology to become a useful surveillance option, its sensitivity for low-grade lesions must be improved. One potential way to accomplish this is to add biomarkers to routine cytologic specimens to define patients at increased risk of progression to cancer. If simple prognostic biomarkers could be developed and validated in histology and cytologic specimens, this would provide additional support for the utility of cytologic brushings in the surveillance of BE. Cytology could then conceivably accomplish the goals of improved efficiency, risk stratification, and decreased costs in BE surveillance programs.

The case for early detection

Early detection represents one of the most promising approaches to reducing the growing cancer burden. It already has a key role in the management of cervical and breast cancer, and is likely to become more important in the control of colorectal, prostate and lung cancer. Early-detection research has recently been revitalized by the advent of novel molecular technologies that can identify cellular changes at the level of the genome or proteome, but how can we harness these new technologies to develop effective and practical screening tests?

[Histopathological diagnosis of Barrett's mucosa and associated neoplasias. Results of a consensus conference of the Working Group for "Gastroenterological Pathology of the German Society for Pathology" on 22 September 2001]

There are a number of difficulties regarding the diagnosis of Barrett's mucosa and the varying grades of neoplasia that may be associated with it. It was therefore the aim of a consensus conference of the "Working Group for Gastroenterological Pathology within the German Society of Pathology" to achieve standardization regarding the following issues: definition and diagnostic criteria for Barrett's mucosa and its discrimination from intestinal metaplasia of the cardia, diagnostic criteria for intraepithelial neoplasia, number of biopsies necessary to establish the diagnosis, significance of additional immunohistochemical and/or molecular biological methods as well as importance of a second opinion in the diagnosis of intraepithelial neoplasia.

Gastrointestinal epithelial dysplasia: detection with new endoscopic techniques

Endoscopic detection of dysplasia currently requires either the presence of a visible lesion (such as a polyp) or the serendipitous sampling of a dysplastic focus during "blind" surveillance biopsies. To accurately and efficiently examine large areas of mucosa during surveillance endoscopy, new methods are required to render dysplasia visible. Spectroscopy and optical coherence tomography are two technologies under active investigation for this purpose. This review presents the basic concepts behind these technologies and discusses their utility in the detection of gastrointestinal dysplasia.

Barrett's esophagus

Barrett's esophagus is an acquired condition resulting from severe esophageal mucosal injury. It still remains unclear why some patients with gastroesophageal reflux disease develop Barrett's esophagus whereas others do not. The diagnosis of Barrett's esophagus is established if the squamocolumnar junction is displaced proximal to the gastroesophageal junction and if intestinal metaplasia is detected by biopsy. Despite this seemingly simple definition, diagnostic inconsistencies remain a problem, especially in distinguishing short segment Barrett's esophagus from intestinal metaplasia of the gastric cardia. Barrett's esophagus would be of little importance were it not for its well-recognized association with adenocarcinoma of the esophagus. The incidence of esophageal adenocarcinoma continues to increase and the 5-year survival rate for this cancer remains dismal. However, cancer risk for a given patient with Barrett's esophagus is lower than previously estimated. Current strategies for improved survival in patients with esophageal adenocarcinoma focus on cancer detection at an early and potentially curable stage. This can be accomplished either by screening more patients for Barrett's esophagus or with endoscopic surveillance of patients with known Barrett's esophagus. Current screening and surveillance strategies are inherently expensive and inefficient. New techniques to improve the efficiency of cancer surveillance are evolving rapidly and hold the promise to change clinical practice in the future. Treatment options include aggressive acid suppression, antireflux surgery, chemoprevention, and ablation therapy, but there is still no clear consensus on the optimal treatment for these patients.

Expression of cyclin B1 in the metaplasia-dysplasia-carcinoma sequence of Barrett esophagus

BACKGROUND

It is known that proliferation is deregulated progressively during carcinogenesis in Barrett esophagus (BE). Cyclin B1 is a key protein for the regulation of G2-M-phase transition during the cell cycle and is essential for initiation of mitosis.

METHODS

Using immunohistochemistry, samples of Barrett metaplastic specialized epithelium (SE; n = 36 samples), low-grade dysplasia (LGD; n = 25 samples), high-grade dysplasia (HGD; n = 25 samples), and invasive adenocarcinoma (CA; n = 46 samples) derived from 50 esophagectomy specimens were investigated for the expression of cyclin B1. The number of cyclin B1 positive cells was determined semiquantitatively. In addition, in SE, LGD, and HGD samples, the pattern of cyclin B1 expression was assessed by determination of the presence of positive cells in four mucosal compartments: the deep glandular zone, the lower crypt zone, the upper crypt zone, and the luminal surface.

RESULTS

Cyclin B1 expression was found in all lesions under investigation. Regarding the percentage of positive cells, a marked increase of cyclin B1 positive cells was observed in SE samples compared with LGD samples and in HGD samples compared with CA samples (chi-square test; P < 0.0001), nevertheless showing a broad overlap between the different lesions. Concerning staining patterns, in the majority of SE samples (72.2%), cyclin B1 positive cells were restricted to the glandular zone and the lower crypt zone. In contrast, an expansion of cyclin B1 positive cells to superficially located zones of the mucosa (the upper crypt zone and/or the luminal surface) was observed in the majority of LGD samples (96.0%) and HGD samples (100%; P < 0.0001).

CONCLUSIONS

Overexpression of cyclin B1 is a frequent and early finding in the metaplasia-dysplasia-carcinoma sequence in BE. It may contribute to the loss of growth control and, subsequently, to the development of tumors in this location.

Predictors of progression in Barrett's esophagus III: baseline flow cytometric variables

OBJECTIVES

Barrett's esophagus develops in 5-10% of patients with gastroesophageal reflux disease and predisposes to esophageal adenocarcinoma. We have previously shown that a systematic baseline endoscopic biopsy protocol using flow cytometry with histology identifies subsets of patients with Barrett's esophagus at low and high risk for progression to cancer. In this report, we further examined cytometric variables to better define the characteristics that best enable DNA cytometry to help predict cancer outcome.

METHODS

Patients were prospectively evaluated using a systematic endoscopic biopsy protocol, with baseline histological and flow cytometric measurements as predictors and with cancer as the outcome.

RESULTS

A receiver operating curve analysis demonstrated that a 4N fraction cut point of 6% was optimal to discriminate cancer risk (relative risk [RR] = 11.7, 95% CI = 6.2-22). The 4N fractions of 6-15% were just as predictive of cancer as were fractions of >15%. We found that only aneuploid DNA contents of >2.7N were predictive of cancer (RR = 9.5, CI = 4.9-18), whereas those patients whose sole abnormality was an aneuploid population with DNA content of < or =2.7 had a low risk for progression. The presence of both 4N fraction of >6% and aneuploid DNA content of >2.7N was highly predictive of cancer (RR = 23, CI = 10-50). S phase was a predictor of cancer risk (RR = 2.3, CI = 1.2-4.4) but was not significant when high-grade dysplasia was accounted for.

CONCLUSIONS

Flow cytometry is a useful adjunct to histology in assessing cancer risk in patients with Barrett's esophagus. Careful examination of cytometric variables revealed a better definition of those parameters that are most closely associated with increased cancer risk.

Predictors of progression in Barrett's esophagus II: baseline 17p (p53) loss of heterozygosity identifies a patient subset at increased risk for neoplastic progression

OBJECTIVES

Most patients with Barrett's esophagus do not progress to cancer, but those who do seem to have markedly increased survival when cancers are detected at an early stage. Most surveillance programs are based on histological assessment of dysplasia, but dysplasia is subject to observer variation and transient diagnoses of dysplasia increase the cost of medical care. We have previously validated flow cytometric increased 4N fractions and aneuploidy as predictors of progression to cancer in Barrett's esophagus. However, multiple somatic genetic lesions develop during neoplastic progression in Barrett's esophagus, and it is likely that a panel of objective biomarkers will be required to manage the cancer risk optimally.

METHODS

We prospectively evaluated endoscopic biopsies from 325 patients with Barrett's esophagus, 269 of whom had one or more follow-up endoscopies, by a robust platform for loss of heterozygosity (LOH) analysis, using baseline 17p (p53) LOH as a predictor and increased 4N, aneuploidy, high-grade dysplasia, and esophageal adenocarcinoma as outcomes.

RESULTS

The prevalence of 17p (p53) LOH at baseline increased from 6% in negative for dysplasia to 57% in high-grade dysplasia (p < 0.001). Patients with 17p (p53) LOH had increased rates of progression to cancer (relative risk [RR] = 16, p < 0.001), high-grade dysplasia (RR = 3.6, p = 0.02), increased 4N (RR = 6.1, p < 0.001), and aneuploidy (RR = 7.5, p < 0.001).

CONCLUSIONS

Patients with 17p (p53) LOH are at increased risk for progression to esophageal adenocarcinoma as well as high-grade dysplasia, increased 4N, and aneuploidy. 17p (p53) LOH is a predictor of progression in Barrett's esophagus that can be combined with a panel of other validated biomarkers for risk assessment as well as intermediate endpoints in prevention trials.

Endoscopic and histologic diagnosis of Barrett esophagus

Endoscopy plays an important role in the identification, diagnosis, and treatment of Barrett esophagus. Short-segment (<2-3 cm) and traditional long-segment (>2-3 cm) Barrett esophagus are distinguished solely on the length of metaplastic tissue above the esophagogastric junction. The histologic hallmark of intestinal metaplasia is required to confirm diagnosis. Biopsy specimens obtained from tissue of presumed Barrett esophagus or an irregular Z line confirm metaplastic glandular mucosa and permit evaluation of dysplastic or neoplastic changes. In the appropriate clinical setting, the use of adjunctive diagnostic techniques may facilitate the diagnosis of Barrett esophagus and sequelae such as dysplasia. Chromoendoscopy with high-resolution or magnified endoscopy is simple, safe, and desirable for surveillance but requires additional procedural time. The use of light-induced fluorescence endoscopy and light-scattering spectroscopy (i.e., optical biopsy) is appealing for the diagnosis and characterization of suspicious lesions. Adjunctive endoscopic techniques and adherence to a protocol for performing biopsies facilitate the early detection and subsequent surveillance of Barrett esophagus.

Dysplasia in Barrett's Esophagus

Dysplasia is the most important marker of progression to invasive cancer in Barrett's esophagus. Intensive endoscopic surveillance with biopsy may identify invasive cancer in a patient with high-grade dysplasia (HGD). Close relationship with an experienced gastrointestinal pathologist and thoracic surgeon will improve treatment decisions and patient outcomes. No intervention is required in patients with low-grade dysplasia (LGD); continued surveillance is recommended. Surgical resection is the currently accepted therapy for high-grade dysplasia. Endoscopic ablative therapy remains experimental.

The diagnosis of low-grade dysplasia in Barrett's esophagus and its implications for disease progression

OBJECTIVE

The reported risk of progression from low-grade dysplasia (LGD) to high-grade dysplasia (HGD) or carcinoma (CA) in Barrett's esophagus varies. However, the validity of a diagnosis of LGD may be questioned because of interobserver variability.

METHODS

A search of the Cleveland Clinic Foundation surgical pathology files between 1986 and 1997 yielded biopsy specimens from 43 patients with Barrett's esophagus diagnosed and coded as LGD. Patients with concurrent or prior diagnoses of HGD or carcinoma were excluded. The LGD cases were randomized and blindly reviewed by three gastrointestinal (GI) pathologists along with cases originally diagnosed as Barrett's esophagus without dysplasia (ND; n = 28), indefinite for dysplasia (IND; n = 14), or HGD (n = 15). Each pathologist classified every biopsy specimen as ND, IND, LGD, or HGD, and interobserver agreements were determined by kappa statistics (K). Follow-up data were available on 25 patients originally diagnosed with LGD. Progression was defined as a subsequent diagnosis of HGD or CA on esophageal biopsy or resection specimens.

RESULTS

Agreement between two GI pathologists for a diagnosis of LGD was fair (K = 0.28) and poor (K = 0.21 and -0.04). Individual GI pathologists agreed with the original diagnosis of LGD in 70%, 56%, and 16% of cases. The 25 patients with follow-up included 21 men and four women (mean age, 67 yr) with a mean follow-up of 26 months (range: 2-84 months). Seven patients (28%) with follow-up developed HGD (five patients) or CA (two patients), 2-43 months (median: 11 months) after a diagnosis of LGD. The individual GI pathologists' diagnosis did not correlate with progression. However, when at least two GI pathologists agreed on LGD, there was a significant association with progression (seven of 17 patients, 41%, p = 0.04). When all three GI pathologists agreed on a diagnosis of LGD, four of five patients progressed (p = 0.012). In contrast, of the eight patients with follow-up and no agreement among GI pathologists for a diagnosis of LGD, none progressed.

CONCLUSIONS

A high degree of interobserver variability is seen in the histological diagnosis of Barrett's esophagus-related LGD. Although the number of observations is low, a consensus diagnosis of LGD among GI pathologists suggests an increased risk of progression from LGD to HGD or carcinoma.

Predictors of progression to cancer in Barrett's esophagus: baseline histology and flow cytometry identify low- and high-risk patient subsets

OBJECTIVE

Barrett's esophagus develops in 5-20% of patients with gastroesophageal reflux disease and predisposes to esophageal adenocarcinoma. The value of endoscopic biopsy surveillance is questioned because most patients do not develop cancer. Furthermore, observer variation in histological diagnosis makes validation of surveillance guidelines difficult because varying histological interpretations may lead to different estimated rates of progression. Thus, objective biomarkers need to be validated for use with histology to stratify patients according to their risk for progression to cancer.

METHODS

We prospectively evaluated patients using a systematic endoscopic biopsy protocol with baseline histological and flow cytometric abnormalities as predictors and cancer as the outcome.

RESULTS

Among patients with negative, indefinite, or low-grade dysplasia, those with neither aneuploidy nor increased 4N fractions had a 0% 5-yr cumulative cancer incidence compared with 28% for those with either aneuploidy or increased 4N. Patients with baseline increased 4N, aneuploidy, and high-grade dysplasia had 5-yr cancer incidences of 56%, 43%, and 59%, respectively. Aneuploidy, increased 4N, or HGD were detected at baseline in all 35 patients who developed cancer within 5 yr.

CONCLUSIONS

A systematic baseline endoscopic biopsy protocol using histology and flow cytometry identifies subsets of patients with Barrett's esophagus at low and high risk for progression to cancer. Patients whose baseline biopsies are negative, indefinite, or low-grade displasia without increased 4N or aneuploidy may have surveillance deferred for up to 5 yr. Patients with cytometric abnormalities merit more frequent surveillance, and management of high-grade dysplasia can be individualized.

Principles and pitfalls of diagnostic test development: implications for spectroscopic tissue diagnosis

Diagnostic spectroscopy has the potential to supplant the time-honored "gold standard" of light microscopy and herald an era of in vivo tissue diagnosis. However, the lessons in disease diagnosis learned by pathologists over the years should not be forgotten. This discussion will focus on the basis principles and pitfalls of diagnostic test development, and how they apply to optical spectroscopy tissue diagnosis.