Narrow band imaging and serology in the assessment of premalignant gastric pathology

Abstract

Background: Patient outcomes in gastric adenocarcinoma are poor due to late diagnosis. Detecting and treating at the premalignant stage has the potential to improve this. Helicobacter pylori is also a strong risk factor for this disease.

Aims: Primary aims were to assess the diagnostic accuracy of magnified narrow band imaging (NBI-Z) endoscopy and serology in detecting normal mucosa, H. pylori gastritis and gastric atrophy. Secondary aims were to compare the diagnostic accuracies of two classification systems using both NBI-Z and white light endoscopy with magnification (WLE-Z) and evaluate the inter-observer agreement.

Methods: Patients were prospectively recruited. Images of gastric mucosa were stored with histology and serum for IgG H. pylori and Pepsinogen (PG) I/II ELISAs. Blinded expert endoscopists agreed on mucosal pattern. Mucosal images and serological markers were compared with histology. Kappa statistics determined inter-observer variability for randomly allocated images among four experts and four non-experts.

Results: 116 patients were prospectively recruited. Diagnostic accuracy of NBI-Z for determining normal gastric mucosa was 0.87(95%CI 0.82–0.92), H. pylori gastritis 0.65(95%CI 0.55–0.75) and gastric atrophy 0.88(95%CI 0.81–0.94). NBI-Z was superior to serology at detecting gastric atrophy: NBI-Z gastric atrophy 0.88(95%CI 0.81-0.94) vs PGI/II ratio < 3 0.74(95%CI 0.62–0.85) p<.0001. Overall NBI-Z was superior to WLE-Z in detecting disease using two validated classifications. Inter-observer agreement was 0.63(95%CI 0.51–0.73).

Conclusions: NBI-Z accurately detects changes in the GI mucosa which currently depend on histology. NBI-Z is useful in the detection of precancerous conditions, potentially improving patient outcomes with early intervention to prevent gastric cancer.

Keywords:

• Endoscopy
• narrow band imaging
• white light endoscopy
• serology
• H. pylori gastritis
• gastric atrophy
• intestinal metaplasia

Acknowledgements

We would like to thank the faculty staff especially Samantha Warburton, Susan Henry and Melanie Lingaya and the equipment support provided by the NIHR Nottingham Biomedical Research Centre. The views expressed are those of the author(s) and not necessarily those of the NHS, the NIHR, or the Department of Health.

Disclosure statement

The authors report no conflict of interest.

Additional information

Funding

This work was supported by the National Institute for Health Research Nottingham Biomedical Research Centre, Nottingham University Hospitals NHS Trust and The University of Nottingham, United Kingdom.