Table 3.

Comparison of predictive accuracy between the 8th TNM-GC and TNM-EC staging systems for AEG and type II patients

Training cohort (N = 705)	Concordance indices
	C index	Bootstrap 95% CI	AIC	P value
TNM-GC system	0.721	0.691–0.751	3174.5	< 0.001*
TNM-EC system	0.690	0.659–0.721	3231.7
Validation cohort (N = 705)
TNM-GC system	0.721	0.692–0.750	3410.4	< 0.001*
TNM-EC system	0.696	0.665–0.726	3458.2
Training cohort (N = 436) for Siewert type II
TNM-GC system	0.724	0.686–0.762	1811.1	0.005*
TNM-EC system	0.694	0.655–0.733	1840.8
Validation cohort (N = 413) for Siewert type II
TNM-GC system	0.723	0.684–0.762	1756.8	< 0.001*
TNM-EC system	0.699	0.659–0.739	1785.2

TNM-GC AJCC 8th gastric cancer staging system, TNM-EC AJCC 8th esophageal cancer staging system, HR hazard ratio, 95% CI 95% confidence interval, AIC Akaike Information Criterion

*P < 0.05, statistical significance