The value of narrowband imaging with magnifying endoscopy in the surveillance of patients with intestinal metaplasia and dysplasia of the gastric mucosa

In the Netherlands, gastric remains one of the most common cancers with over
2000 new cases every year. Symptoms are generally absent until an advanced
stage of disease, when there are limited treatment options. Therefore,
diagnosis of pre-malignant gastric lesions before malignant progression could
improve the prognosis of these patients. The surveillance of these premalignant
lesions could lead to improved survival of these patients. However, the
histological diagnosis of these premalignant lesions is usually disregarded in
clinical practice, as no guidelines exist for the surveillance or treatment of
patients with these lesions. Periodical surveillance is common in dysplasia
patients, but not in patients with intestinal metaplasia or atrophic gastritis.
Recent investigation have demonstrated that current surveillance of
pre-malignant gastric lesions shows great discrepancy with the substantial
gastric cancer risk of these lesions.
Although image quality of standard endoscopes has improved dramatically over
the past decades, endoscopic evaluation of the condition of the gastric mucosa
still correlates poorly with histological findings. Therefore, a diagnosis of
pre-malignant gastric lesions remains dependant on random biopsy sampling
during conventional gastroscopy.
A promising technique is narrow-band imaging in combination with magnifying
endoscopy (NBI-ME). The principle of this new technique is based on
modification of the spectral characteristics of the optical filter in the light
source, which leads to enhancement of mucosal structures. With use of different
narrow-band filters in combination with image magnification, mucosal structures
can be very clearly demonstrated, among others resulting in increased contrast.
Therefore it can be expected that the use of this technique for targeted biopsy
sampling can increase the diagnostic yield of endoscopy for primary detection
of pre-malignant gastric lesions. However, the additional value of narrowband
imaging with magnification endoscopy to conventional endoscopy in the
surveillance of patients with pre-malignant gastric lesions is yet unclear.
Also serum levels of pepsinogen I and II and gastrin 17 are possible parameters
to predict the presence of intestinal metaplasia and dysplasia. However, the
exact predictive value of these parameters in a population of patients with
intestinal metaplasia and dysplasia is unclear.

To determine the additional value of NBI-ME to conventional endoscopy in the
surveillance of patients with intestinal metaplasia and dysplasia, i.e. to
evaluate whether the use of NBI-ME is superior to conventional endoscopy in the
detection of intestinal metaplasia or dysplasia, using histology as reference
value.

1.The presence of serum H. pylori antibodies, pepsinogen and gastrin 17 will be
evaluated.
2. Gastroscopy: A single endoscopic procedure, including conventional endoscopy
and NBI-ME, will be performed by an expert endoscopist with an endoscope that
can be used for both conventional endoscopy and NBI-ME. Biopsy samples will be
obtained.

Patients will be asked to give a blood sample. Gastroscopy with NBI-ME is
considered to be a low risk intervention (complications: less than 1 in 3000
gastroscopies).