Prediction of colorectal tumor grade and invasion depth through narrow-band imaging scoring

Table 1 Relationship of narrow-band imaging findings with tumor grade and invasion depth

	Dependent variable	Independent variable1	Univariate analysis		Multivariate analysis
			Odds ratio (95%CI)	P value	Odds ratio (95%CI)	P value
Tumor grade	Probability of cancer	Irregular (tubular type)	0.034 [0.013, 0.088]	< 0.0001	46.81 [14.55, 184.48]	< 0.0001
	AUC = 0.89	Irregular (papillary type)	0.034 [0.013, 0.088]	< 0.0001	47.21 [7.51, 512.05]	< 0.0001
		Avascular area	0.048 [0.006, 0.376]	< 0.0001	16.3 [1.69, 396.35]	0.06
Invasion depth	Probability of SM deep invasive cancer2	Disrupted vessels	0.169 [0.058, 0.488]	0.0004	3.63 [0.98, 17.69]	0.0714
	AUC = 0.70	Thick vessels	0.509 [0.127, 2.037]	0.3325	22.86 [2.55, 537.18]	0.0133

¹Colorectal lesions were classified into tubular and papillary types based on narrow-band imaging observations of the histopathologic appearances and proliferation patterns;

²Submucosa (SM) deep invasive cancer: SM invasion depth ≥ 1000 μm. SM: Submucosa; AUC: Area under the curve.

Table 2 Narrow-band imaging scoring system for predicting tumor grade and invasion depth

	Variable	Value3	Score4
Tumor grade1	Surface pattern = regular/irregular	Irregular (tubular type)	5
		Regular (tubular type)	1
		Irregular (papillary type)	3
		Regular (papillary type)	0
	Vascular pattern = avascular area	Present	1
		Absent	0
Invasion depth2	Vascular pattern = disrupted vessels	Present	3
		Absent	1
	Vascular pattern = thick vessels	Present	6
		Absent	1

¹Tumor grade: Total score ≥ 1, suggestive of cancer; total score < 1, suggestive of adenoma [sensitivity, 0.97; specificity, 0.24; area under the curve (AUC) = 0.89];

²Invasion depth: Total score ≥ 9, suggestive of submucosa (SM) invasion depth ≥ 1000 μm; total score < 9, suggestive of SM invasion depth < 1000 µm (sensitivity, 0.56; specificity, 1.0; AUC = 0.80);

³Colorectal lesions were classified into tubular and papillary types based on narrow-band imaging observations of the histopathologic appearances and proliferation patterns;

⁴Scores were calculated based on the parameter estimates and standard errors in the multivariate logistic regression model. The adjusted value (z score or t score) was obtained by dividing the partial regression coefficient by the standard error of the mean to yield the maximum possible difference; the sum was subsequently considered. Receiver operating characteristic curve modeling was used to determine a cut-off with approximate values.

Table 3 Relationship of narrow-band imaging findings to colorectal tumor tissue architecture

	Variable	Classification1	Tissue architecture
			Lining epithelium degeneration/ prolapse	Glandular duct arrangement	Superficial differentiation	Superficial desmoplastic reaction	Muscularis mucosae	Granuloma formation
Surface pattern	Visible/Invisible	Tubular	a	a	a	a	a	a
		Papillary	b	c	c	a	a	a
	Clarity	Tubular	a	a	c	c	a	a
		Papillary	a	a	c	n.a.	a	a
	Regular/Irregular	Tubular	a	a	b	c	a	b
		Papillary	a	a	c	n.a.	a	a
Vascular pattern	Disturbed arrangement	Tubular	a	a	a	a	a	a
		Papillary	a	a	b	c	a	a
	Disrupted vessels	Tubular	a	a	c	a	a	a
		Papillary	a	a	c	a	a	a
	Varying caliber	Tubular	a	a	c	a	a	b
		Papillary	c	c	c	a	b	b
	Size irregularity	Tubular	a	a	a	a	a	a
		Papillary	a	a	b	c	a	a
	Thick vessels	Tubular	a	a	b	a	a	c
		Papillary	a	c	c	c	c	b
	Avascular area	Tubular	a	a	a	a	a	a
		Papillary	c	c	c	b	c	c
	Vessel meandering	Tubular	c	c	c	c	c	c
		Papillary	a	b	c	c	a	a

¹Colorectal lesions were classified into tubular and papillary types based on narrow-band imaging observations of the histopathologic appearances and proliferation patterns. ^aP < 0.05; 0.05 < ^bP < 0.1; ^cP > 0.1. n.a.: Not available.

Table 4 Relationships of tumor grade and invasion depth with tissue architecture n (%)

	Tumor grade				Invasion depth
	Variable	Adenoma(n = 81)	Cancer1(n = 49)	P value	SM invasion depth ≥ 1000 μm (n = 49)	SM invasion depth < 1000 μm (n = 31)	P value
Lining epithelium degeneration/prolapse	Absent	69 (85.2)	20 (40.8)		20 (40.8)	1 (3.2)
	Present	12 (14.8)	29 (59.2)	< 0.0001	29 (59.2)	30 (96.8)	0.001
Irregularity in glandular duct size/arrangement	Absent	54 (66.7)	10 (20.4)		10 (20.4)	1 (3.2)
	Present	27 (33.3)	39 (79.6)	< 0.0001	39 (79.6)	25 (80.6)	0.113
Superficial differentiation	Well-diff.		42 (85.7)		42 (85.7)	20 (64.5)
	Moderately diff.		7 (14.3)		7 (14.3)	10 (32.3)
	Poorly diff.		0 (0.0)		0 (0.0)	1 (3.2)	0.027
Superficial desmoplastic reaction	Absent	81 (100)	47 (95.9)		47 (95.9)	17 (54.8)
	Present	0 (0.0)	2 (4.1)	0.273	2 (4.1)	14 (45.2)	< 0.0001
Loss of muscularis mucosae	Absent	0 (0.0)	3 (6.1)		3 (6.1)	29 (93.5)
	Present	81 (100)	46 (93.9)	0.099	46 (93.9)	2 (6.5)	< 0.0001
Granuloma formation	Absent	80 (98.8)	44 (89.8)		44 (89.8)	19 (61.3)
	Present	1 (1.2)	5 (10.2)	0.054	5 (10.2)	2 (38.7)	0.002

¹Intramucosal cancer (confined to the mucosa); diff.: Differentiated; SM: Submucosa.