Effective use of the Japan Narrow Band Imaging Expert Team classification based on diagnostic performance and confidence level

Table 1 The relation between the Japan Narrow Band Imaging Expert Team classification and the histopathological diagnosis at Sano Hospital

OA (HC), n	HP, SSP	LGIN	HGIN, S-SMC	D-SMC
Type 1	653 (564)	90 (48)	0	0
Type 2A	570 (440)	4459 (4289)	119 (118)	0
Type 2B	0	93 (42)	93 (65)	22 (21)
Type 3	0	0	2 (2)	37 (35)

OA: Overall cases; HC: High confidence cases; HP: Hyperplastic polyp; SSP: Sessile serrated polyp; LGIN: Low grade intramucosal neoplasia; HGIN: High grade intramucosal neoplasia; S-SMC: Shallow submucosal invasive cancer; D-SMC: Deep submucosal invasive cancer.

Table 2 Reports about diagnostic performance of the Japan Narrow Band Imaging Expert Team Classification

First author	Cases, n	Participants	Study design
Sumimoto et al[9]	2933	3 experts	A retrospective analysis	in vivo	Single center
Komeda et al[10]	199	3 experts	A retrospective analysis	in vitro	Single center
Minoda et al[11]	40	11 experts and 11 non-GI trainees	A retrospective analysis	in vitro	Single center
Our study	6138	5 experts and 3 trainees	A retrospective analysis	in vivo	Single center

Table 3 Neoplasia (type 2A) vs non neoplasia (type 1)

First author	Sumimoto	Komeda	Our study
Accuracy, %	99.0	98.0	88.8
Sensitivity, %	99.8	99.3	98.1
Specificity, %	87.5	85.7	53.3
PPV, %	99.1	98.5	88.9
NPV, %	97.5	92.3	87.9

PPV: Positive predictive value; NPV: Negative predictive value.

Table 4 Malignant neoplasia (type 2B, 3) vs benign neoplasia (type 2A)

First author	Sumimoto	Komeda	Our study
Accuracy, %	80.7	91.9	96.1
Sensitivity, %	71.9	81.0	56.4
Specificity, %	84.7	96.9	98.2
PPV, %	67.8	92.2	62.3
NPV, %	87.0	91.9	97.7

PPV: Positive predictive value; NPV: Negative predictive value.

Table 5 Deep submucosal invasive cancer (type 3) vs other neoplasia (type 2A, 2B)

First author	Sumimoto	Komeda	Our study
Accuracy, %	96.4	93.5	99.6
Sensitivity, %	55.4	29.4	62.7
Specificity, %	99.8	100.0	100.0
PPV, %	95.2	100.0	94.9
NPV, %	96.4	93.4	99.6

PPV: Positive predictive value; NPV: Negative predictive value.

Table 6 Comparison with Narrow Band Imaging International Colorectal Endoscopic classification

Diagnosis	Neoplasia vs non neoplasia1		Deep submucosal invasive cancer vs other neoplasia2
Classification	JNET	NICE[5]	JNET	NICE[6]
Overall, n	5891	236	4825	400
Accuracy, %	91.3	89	96.8	90
Sensitivity, %	99.0	98	51.0	92
Specificity, %	56.2	69	99.1	88
PPV, %	91.2	87	74.5	88
NPV, %	92.2	95	97.6	92
High confidence rate, %	93.1	75	92.9	50

¹Neoplasia vs non neoplasia; JNET 1 vs 2A,2B and NICE 1 vs 2.

²Deep submucosal invasive cancer vs other neoplasia; JNET 2A,2B vs 3 and NICE 2 vs 3. PPV: Positive predictive value; NPV: Negative predictive value; JNET: Japan Narrow Band Imaging Expert Team; NICE: Narrow Band Imaging International Colorectal Endoscopic.