Table 3.

Performance metrics for integrated I-score (two-category) models and reference models

Models	Discovery cohort				Validation cohort
	iAUCa	Harrell’s C-index	AIC		iAUC	Harrell’s C-index	AIC
TNM stage model b	0.674	0.694 (0.640–0.749)	615.6		0.645	0.651 (0.596–0.705)	742.3
I-score model	0.584	0.592 (0.532–0.651)	647.4		0.592	0.588 (0.533–0.644)	758.6
TNM Stage & I-score model b	0.699	0.711 (0.651–0.772)	613.5		0.673	0.679 (0.623–0.736)	736.4
Clinicopathologic model c	0.698	0.728 (0.676–0.781)	614.2		0.671	0.685 (0.627–0.743)	739.2
Full model c	0.717	0.742 (0.688–0.795)	610.9		0.684	0.695 (0.639–0.751)	734.8

Data in parentheses are 95% confidence intervals

iAUC integrated area under the curve, Harrell’s C-index Harrell’s concordance index, AIC Akaike information criterion

^aiAUC refers to the integrated area under the ROC curve

^b TNM-stage model vs. TNM Stage & I-score model: likelihood ratio P = 0.044

^cClinicopathologic model (TMN stage & differentiation grade & adjuvant chemotherapy) vs. Full model: likelihood ratio P = 0.022