Diagnostic performance of narrow-band imaging international colorectal endoscopic and Japanese narrow-band imaging expert team classification systems for colorectal cancer and precancerous lesions

Table 1 Demographic characteristics of 87 patients with 125 colorectal lesions

Variables	Number
Patients	87
Lesions	125
Sex, male/female	61; 26
Age in yr, mean ± SD; range	59.9 ± 10.6; 34-89
Location
Proximal colon	42
Distal colon	61
Rectum	22
Size in mm, mean ± SD; range	14.3 ± 0.7; 4-45
5	9
6-10	44
11-20	58
≥ 20	14
Morphology
Ip	22
Isp	39
Is	30
IIa	31
IIb	3
Pathology
Hyperplastic or sessile serrated lesion	13
Tubular adenoma	67
Tubulovillous adenoma	27
Low-grade intramucosal neoplasia	1
High-grade intramucosal neoplasia	3
Superficial submucosal invasive cancer	10
Deep submucosal invasive cancer	4

Table 2 Performance characteristics of each type of the narrow-band imaging international colorectal endoscopic classification

NICE	Group1	Sensitivity, % (95%CI)	Specificity, % (95%CI)	Accuracy, % (95%CI)	PPV, % (95%CI)	NPV, % (95%CI)
Type 1	HEE	84.6 (65.5-100.0)	94.9 (93.7-96.2)	93.9 (90.8-96.9)	65.9 (55.6-76.3)	98.2 (95.9-100.0)
	LEE	82.1 (60.0-100.0)	93.8 (91.5-96.0)	92.5 (88.4-96.7)	60.4 (46.2-74.5)	97.8 (95.2-100.0)
		P = 0.637	P = 0.105	P = 0.275	P = 0.275	P = 0.376
Type 2	HEE	91.4 (88.7-94.0)	86.3 (77.8-94.7)	90.7 (89.5-91.8)	97.7 (96.4-99.0)	61.2 (56.0-66.4)
	LEE	89.8 (87.5-92.1)	84.3 (75.9-92.8)	89.1 (86.8-91.4)	97.3 (96.0-98.7)	56.6 (50.6-62.6)
		P = 0.105	P = 0.456	P = 0.043 0.1	P = 0.121	P = 0.100
Type 3	HEE	91.7 (55.8-100.0)	97.0 (92.2-100.0)	96.8 (91.5-100.0)	54.0 (-2.7-100.0)	99.7 (99.5-100.0)
	LEE	83.3 (47.5-100.0)	96.4 (92.1-100.0)	96.0 (90.7-100.0)	45.8 (0.7-91.0)	99.4 (98.2-100.0)
		P = 0.042	P = 0.487	P = 0.367	P = 0.376	P = 0.346

¹Three endoscopists in each group.

CI: Confidence interval; HEE: Highly experienced endoscopist; LEE: Less-experienced endoscopist; NPV: Negative predictive value; PPV: Positive predictive value; NICE: Narrow-band imaging international colorectal endoscopic.

Table 3 Performance characteristics of each type of the Japanese narrow-band imaging expert team classification

JNET	Group1	Sensitivity, % (95%CI)	Specificity, % (95%CI)	Accuracy, % (95%CI)	PPV, % (95%CI)	NPV, % (95%CI)
Type 1	HEE	87.1 (76.2-98.2)	97.3 (95.1-99.5)	95.5 (92.4-98.5)	74.1 (60.0-88.1)	98.5 (97.2-99.8)
	LEE	84.6 (65.5-100.0)	96.4 (94.2-98.6)	95.2 (91.8-98.6)	73.4 (58.8-88.0)	98.2 (96.0-100.0)
		P = 0.369	P = 0.261	P = 0.637	P = 0.822	P = 0.500
Type2A	HEE	82.5 (78.5-86.5)	90.0 (81.7-98.3)	81.9 (72.7-91.1)	93.3 (77.6-108.9)	58.5 (47.0-69.9)
	LEE	82.5 (81.0-84.0)	91.1 (86.3-95.9)	84.5 (83.4-85.7)	96.7 (95.0-98.4)	62.1 (60.3-63.9)
		P = 0.817	P = 0.637	P = 0.099	P = 0.376	P = 0.077
Type 2B	HEE	53.8 (34.7-73.0)	84.2 (73.1-95.4)	81.4 (69.2-93.5)	31.5 (16.4-46.6)	92.2 (81.5-100.0)
	LEE	51.3 (29.2-73.4)	84.8 (81.0-88.7)	81.3 (75.6-87.1)	28.3 (14.2-42.3)	93.8 (90.8-96.7)
		P = 0.817	P = 0.825	P = 0.825	P = 0.268	P = 0.825
Type 3	HEE	91.7 (55.8-100.0)	98.1 (94.9-100.0)	97.9 (93.7-100.0)	63.2 (16.4-100.0)	99.7 (98.5-100.0)
	LEE	83.3 (47.5-100.0)	98.4 (96.3-100.0)	97.9 (94.8-100.0)	63.3 (25.4-100.0)	99.4 (98.3-100.0)
		P = 0.456	P = 0.822	P = 0.856	P = 0.891	P = 0.817

¹Three endoscopists in each group.

CI: Confidence interval; HEE: Highly experienced endoscopist; LEE: Less-experienced endoscopist; NPV: Negative predictive value; PPV: Positive predictive value; JNET: Japanese narrow-band imaging expert team.