Magnifying narrow-band imaging of surface maturation in early differentiated-type gastric cancers after Helicobacter pylori eradication

Even after successful Helicobacter pylori eradication, primary or metachronous gastric cancers are sometimes discovered. The endoscopic features of these cancers may be modified by controlling inflammation. Characteristic findings for such lesions in terms of narrow-band imaging with magnifying endoscopy (NBI-ME) and histopathology need to be clarified to allow accurate diagnosis. Distinctive NBI-ME characteristics were examined retrospectively in intramucosal or minimally submucosal and differentiated-type adenocarcinomas from a successful eradication group (42 patients, 50 lesions) and a non-eradicated control group (44 patients, 50 lesions) matched in age and sex. A "gastritis-like" appearance under NBI-ME was characterized by uniform papillae and/or tubular pits with a whitish border, regular or faint microvessels and unclear demarcation, resembling the adjacent noncancerous mucosa. Histological differentiation at the luminal surface of the cancer was evaluated according to Ki-67 immunoreactivity restricted at the middle or lower portion of the tubules. NBI-ME alteration was prospectively confirmed in 29 patients (30 lesions) after eradication therapy. The frequency of a "gastritis-like" appearance was 44 % (22/50) for the eradication group, which was significantly higher than the 4 % (2/50) for the control group (p < 0.001). In the eradication group, the "gastritis-like" appearance was significantly correlated with histological surface differentiation (p < 0.001). In the prospective study, NBI-ME showed changes to heterogeneous papillary microstructures in 43 % (10/23) of the lesions after successful eradication at short-term follow-up. Identification of surface maturation under NBI-ME offers a promising approach for accurate diagnosis of early gastric cancers after successful eradication.