Table 3. C-index analysis for radiomics index, cTNM, pTNM and integrated model.

Variables	Training cohort (OS)			Validation cohort (OS)
	C-index (95% CI)	P		C-index (95% CI)	P
a, C-index was compared between cTNM stage and radiomics index;b, C-index was compared between pTNM stage and radiomics index; c, C-index was compared between clinical-pathologic model and integrated model (clinical-pathologic-radiomics);d, C-index was compared between clinical-pathologic model and radiomics index;e, C-index was compared between pTNM stage and integrated model (clinical-pathologic-radiomics); f, C-index was compared between radiomics index and integrated model (clinical-pathologic-radiomics); cTNM, clinical TNM stage; pTNM, pathological TNM; OS, overall survival.
Radiomics index	0.648 (0.619−0.677)	−		0.621 (0.578−0.665)	−
cTNM	0.544 (0.515−0.572)	<0.001a		0.512 (0.467−0.556)	<0.001a
pTNM	0.654 (0.630−0.679)	0.331b		0.631 (0.590−0.671)	0.351b
Clinical-pathologic model	0.669 (0.642−0.695)	<0.001c		0.657 (0.614−0.700)	0.035c
		0.076d			0.072d
Integrated model	0.694 (0.667−0.720)	<0.001e		0.674 (0.630−0.718)	<0.001e
		<0.001f			<0.001f