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

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.