Table 3.

Studies evaluating the horizontal extent (DL) of early gastric cancer on narrow-band imaging with or without magnification

Ref.	Endoscopic technique	Aim of the study	Results
Okada et al[166]	NBI-ME	Assessment the comparative relationship between NBI-ME images and histopathological findings in patients with UD-type EGCs prior to either ESD or surgery	NBI-ME images of UD-type EGCs proved to be very closely related to the histopathological findings
Nonaka et al[167]	NBI-ME	Estimating a DL on NBI-ME in comparison with biopsy findings as a gold-standard	The DL that could be recognized at 2 points on the orifice and anal sides of each lesion during ME-NBI was consistent with the pathological findings in 22 patients with 0-IIc lesions, 7 with 0-IIb lesions, and 2 with 0-IIb + IIc lesions, showing an accuracy of 100%
Kiyotoki et al[168]	NBI-ME vs ICC	Evaluated the usefulness of NBI-ME for determining the tumor margin compared with ICC (indigocarminechromoendoscopy)	The rate of accurate marking of the ME-NBI group was significantly higher than that of the ICC group (97.4% vs 77.8%, respectively; P = 0.009)
Nagahama et al[169]	NBI-ME vs CE	To investigate the usefulness and limitations of NBI-ME when CE is unsuccessful for determining the horizontal extent of EGC	The proportion of cancers showing unclear margins using CE was 18.9% (66/350). Of these, 62 of 66 cancers were examined using ME with NBI, with the entire margins successfully delineated in 72.6% (45/62) of the lesions that had shown unclear margins using CE. The success rate was 0% for undifferentiated cancers, significantly lower than that for differentiated lesions (P < 0.00001)

UD-type EGCs: Undifferentiated-type EGCs; ESD: Endoscopic submucosal dissection; ICC: Indigo carmine chromoendoscopy; NBI-ME: Narrow-band imaging with or without magnification.