Evaluation of a minimally invasive cell sampling device coupled with assessment of trefoil factor 3 expression for diagnosing Barrett's esophagus: a multi-center case-control study

Abstract

Background: Barrett's esophagus (BE) is a commonly undiagnosed condition that predisposes to esophageal adenocarcinoma. Routine endoscopic screening for BE is not recommended because of the burden this would impose on the health care system. The objective of this study was to determine whether a novel approach using a minimally invasive cell sampling device, the Cytosponge, coupled with immunohistochemical staining for the biomarker Trefoil Factor 3 (TFF3), could be used to identify patients who warrant endoscopy to diagnose BE.

Methods and findings: A case-control study was performed across 11 UK hospitals between July 2011 and December 2013. In total, 1,110 individuals comprising 463 controls with dyspepsia and reflux symptoms and 647 BE cases swallowed a Cytosponge prior to endoscopy. The primary outcome measures were to evaluate the safety, acceptability, and accuracy of the Cytosponge-TFF3 test compared with endoscopy and biopsy. In all, 1,042 (93.9%) patients successfully swallowed the Cytosponge, and no serious adverse events were attributed to the device. The Cytosponge was rated favorably, using a visual analogue scale, compared with endoscopy (p < 0.001), and patients who were not sedated for endoscopy were more likely to rate the Cytosponge higher than endoscopy (Mann-Whitney test, p < 0.001). The overall sensitivity of the test was 79.9% (95% CI 76.4%-83.0%), increasing to 87.2% (95% CI 83.0%-90.6%) for patients with ≥3 cm of circumferential BE, known to confer a higher cancer risk. The sensitivity increased to 89.7% (95% CI 82.3%-94.8%) in 107 patients who swallowed the device twice during the study course. There was no loss of sensitivity in patients with dysplasia. The specificity for diagnosing BE was 92.4% (95% CI 89.5%-94.7%). The case-control design of the study means that the results are not generalizable to a primary care population. Another limitation is that the acceptability data were limited to a single measure.

Conclusions: The Cytosponge-TFF3 test is safe and acceptable, and has accuracy comparable to other screening tests. This test may be a simple and inexpensive approach to identify patients with reflux symptoms who warrant endoscopy to diagnose BE.

Conflict of interest statement

The Addenbrooke's Hospital Human Research Tissue Bank, supported by the NIHR Cambridge Biomedical Research Centre, supported this study. This study was funded by a project grant from Cancer Research UK. The device was designed by RCF and her research team in between 2009 and 2010. Patents and a trademark were filed in 2010 by the Medical Research Council (MRC). The BEST2 study was designed in 2010 and the device was manufactured for the specific purpose of this study following a letter of no objection from the Medical Health Regulatory Agency. In 2013 the MRC licensed the technology to Covidien GI Solutions. They have had no influence in any way on the design, conduct or analysis of this trial and the manuscript was not disclosed to them until after acceptance for publication. RCF, MOD and PLS are named inventors on patents pertaining to the Cytosponge and related assays. They have not received any financial benefits to date. Since December 2013, after completion of this study, PLS is now employed partly by Covidien GI Solutions. All other authors have no conflicts of interest to declare. RCF has programmatic funding from the Medical Research Council and infrastructure support from the Biomedical Research Centre and the Experimental Medicine Centre. MDDR has received travel reimbursement for conferences (Abbvie 2014), honoraria (Dr Falk 2013), unrestricted grant research (Olympus 2014) and shares (AstraZeneca, held for >20 years).

Figures

Figure 1. Study CONSORT diagram detailing the flow of control and Barrett's esophagus patients (cases) through the study.

Patients who were unable to swallow the Cytosponge or whose Cytosponge sample failed processing were excluded from the study. Exact numbers of control and BE patients who successfully completed the study are noted.

Figure 2. Acceptability of endoscopy and the Cytosponge test.

Patients were asked to rate the procedures using a visual analogue acceptability scale after swallowing the Cytosponge and after endoscopy. The colors representing the different acceptability scores are shown on the right-hand side, with 0 representing the worst experience ever, 5 representing a neutral experience, and 10 representing the best experience ever. The dotted red line marks the boundary between mildly unpleasant or worse (left of the line, score of 0–3) and acceptable scores (right of the line, score of 4 or more), for ease of comparison between the two procedures.

Figure 3. TFF3 immunohistochemical staining of Cytosponge samples.

TFF3 staining was performed on all Cytosponge samples to test the sensitivity and specificity of the Cytosponge-TFF3 test for diagnosing BE. TFF3 was scored in a binary fashion, with samples with one or more TFF3-positive goblet cells being classed as positive. Shown are immunohistochemical images illustrating examples of TFF3-negative and-positive staining at low magnification (100×) and high magnification (400×).

Figure 4. Modeling of Cytosponge-TFF3 testing and risk stratification in the primary care population with reflux symptoms.

Extrapolation of findings to a hypothetical population of 10,000 individuals with reflux symptoms using a sensitivity and specificity of 79.9% and 92.4%, respectively, for the TFF3 screen, and a sensitivity and specificity of 86% (95% CI of 65%–96%) and 100% (95% CI of 94.6%–100%), respectively, for TP53 mutation screening for detection of HGD. The assumed prevalence of BE was 3%. In patients found to be high risk, endoscopy within 6–8 wk would be recommended. For low-risk patients, a repeat Cytosponge-TFF3 test would be performed at an interval of several years (exact timing to be determined) in case they had become TP53 positive over this time period. In the TFF3-negative arm, the repeat Cytosponge testing might not be necessary. If it took place, repeat testing would be recommended within 6 to 8 wk of the delivery of the TFF3-negative results.