 |
Confocal laser endomicroscopy has also been used to diagnose gastric cancer
and precancerous conditions. Endomicroscopy was performed on five ex vivo
gastrectomy specimens and in upper gastrointestinal endoscopies in vivo in
eight patients. Acriflavine hydrochloride dyewas used for ex vivo
examinations, and intravenous fluorescein sodium for in vivo examinations. A
standard upper endoscopy examination was carried out, during which confocal
images were obtained at standardized locations in the gastric antrum, body,
and cardia, before biopsy specimens were taken from the same areas for
histopathology. Confocal diagnostic criteria were established by comparison
with histopathology as the gold standard. Five endoscopists who were blinded
to the histological findings independently scored the confocal images on a
template. The interobserver correlation was analyzed using kappa statistics.
A total of 2766 confocal images from 132 different locations were obtained
and compared with the histological findings in 44 biopsy specimens.
Diagnostic confocal features were established for normal gastric mucosa,
chronic gastritis (presence of chronic inflammatory cells), intestinal
metaplasia (goblet cells), and cancer (architectural atypia, increased
nuclear-cytoplasmic ratio, chromatin condensation). Using these diagnostic
features, a prospective and blinded evaluation showed that the presence of
gastric cancer was capable of being predicted from confocal images with a
high degree of accuracy (sensitivity 84%; specificity 95%; accuracy 80%).
The kappa statistics showed that the interobserver agreement figures on the
presence of intestinal metaplasia and cancer for the various sites (antrum,
body, cardia) were 0.83, 0.89, and 0.63, respectively.
Confocal laser endoscopy allows immediate in vivo diagnosis of mucosal
neoplasia and preneoplasia. Diagnoses of intestinal metaplasia and gastric
carcinoma can be made using the criteria described above with a reliable
level of interobserver agreement. This allows cellular diagnoses during
endoscopy, whereas intestinal metaplasia was previously only capable of
being diagnosed on the basis of the histopathology. In populations at risk
of gastric cancer, confocal endoscopy has potential clinical applications in
connection with screening for gastric neoplasia and preneoplasia. |
