Narrow-band imaging without magnification for detecting early esophageal squamous cell carcinoma

Table 1 Histopathologic diagnosis by hematoxylin and eosin staining

Method	No. of endoscopic findings	SCC		Esophagitis
		In situ	Intramucosal
Conventional	6	3	3	0
NBI	25	5	4	16
Lugol	42	5	4	33

NBI: Narrow-band imaging; SCC: Squamous cell carcinoma.

Table 2 Cases of squamous cell carcinoma (macroscopic and histopathologic findings)

Case	Macroscopic classification by conventional endoscopy	Size(mm)	Location at esophagus	Histopathologic examination
161	n/i	10	Thoracic	Intramucosal
175	0-IIc	50	Thoracic	In situ
72	0-IIc	30	Thoracic	Intramucosal
15	0-IIb	20	Thoracic	In situ
94	0-IIc	50	Thoracic	Intramucosal
64	0-IIb	20	Thoracic	In situ
115	n/i	20	Thoracic	In situ
119	n/i	10	Thoracic	In situ
74	0-IIb	25	Thoracic	Intramucosal

n/i: Not indentified.

Table 3 Comparison of performance across methods (95% confidence interval) (%)

	Conventional endoscopic examination	NBI	Lugol’s solution
Sensitivity	66.7 (35.9-97.5)	100 (100-100)	100 (100-100)
Specificity	100 (100-100)	86.7 (80.6-92.7)	72.5 (64.5-80.5)
PPV	100 (100-100)	36 (17.2-54.8)	21.4 (9.0-33.8)
NPV	97.6 (98.4-100)	100 (100-100)	100 (100-100)
Accuracy	97.7 (95.1-100)	87.6 (81.9-93.3)	74.4 (66.9-81.9)
PLR	n/c	7.5	3.6
NLR	0.33	0	0

NBI: Narrow-band imaging; PPV: Positive predictive value; NPV: Negative predictive value; PLR: Positive likelihood ratio; NLR: Negative likelihood ratio; n/c: Not calculable.

Table 4 Comparison of diagnostic performance of the three procedures for lesions < 10 mm and > 10 mm (%)

	Conventional examination		NBI		Lugol’s solution
	<10 mm	>10 mm	<10 mm	>10 mm	<10 mm	>10 mm
Sensitivity (95% CI)	0 (0-0)	85.7 (59.8-100)	100 (100-100)	100 (100-100)	100 (100-100)	100 (100-100)
Specificity (95% CI)	100 (100-100)	100 (100-100)	90 (84.6-95.4)	96.7 (93.5-100)	75.8 (68.2-83.5)	96.7 (93.5-100)
PPV (95% CI)	n/c	100 (100-100)	14.3 (4.0-32.6)	63.6 (35.2-92.1)	6.5 (2.2-15.1)	63.6 (35.2-92.1)
NPV (95% CI)	98.4 (96.1-100)	99.20 (97.6-100)	100 (100-100)	100 (100-100)	100 (100-100)	100 (100-100)
Accuracy (95% CI)	98.4 (96.1- 100)	99.2 (97.6-100)	90.2 (84.9-95.4)	96.9 (93.8-100)	76.2 (68.7-83.8)	96.9 (93.8-99.9)
PLR	n/c	n/c	10	30	4.1	30
NLR	1	0.1	0	0	0	0

n/c: Not calculable; NBI: Narrow-band imaging; PPV: Positive predictive value; NPV: Negative predictive value; PLR: Positive likelihood ratio; NLR: Negative likelihood ratio.