TABLE 1.

Clinical characteristics of enrolled patients from the multicenter cohorts

	Discovery cohort		Training cohort	Internal validation cohort	External validation cohort
	Guangzhou cohort	Beijing discovery cohort	Beijing training cohort	Beijing validation cohort	Integrated external cohort
	(N = 28)	(N = 30)	(N = 67)	(N = 67)	(N = 52)
Age
≥60	8	17	30	36	40
< 60	20	13	37	31	12
Gender
male	25	28	60	59	37
female	3	2	7	8	15
Tumor location
Upper	4	3	17	17	14
Middle	18	19	37	36	31
Lower	6	8	13	14	7
Tumor differentiation
Well	7	3	7	4	15
Moderate	16	20	36	35	22
Poor	5	7	24	28	15
Clinical T stage
T2	8	2	3	4	13
T3	20	11	42	41	32
T4	0	16	22	22	7
Clinical N stage
N0	0	3	8	13	25
N1, N2, N3	28	27	59	54	27
Clinical M stage
M0	28	30	67	67	52
M1	0	0	0	0	0
Clinical TNM stage
II	8	5	7	14	26
III	20	25	60	53	26
nCRT response
pCR	11	11	22	23	17
< pCR	17	19	45	44	35

Abbreviations: nCRT, neoadjuvant chemoradiotherapy; pCR, pathological complete response; < pCR, less than pCR.