Table 1.

Characteristics of patients used to evaluate MSI status

	Training cohort (n = 142)			Validation cohort (n = 59)
Characteristic	MSI-H	MSS	p value	MSI-H	MSS	p value
Age (years)			1			0.738
< 65	19 (59.37)	65 (59.09)		8 (61.54)	32 (69.57)
≥ 65	13 (40.63)	45 (40.91)		5 (38.46)	14 (30.43)
Sex			0.644			0.037
Male	23 (71.88)	84 (76.36)		6 (46.15)	36 (78.26)
Female	9 (28.12)	26 (23.64)		7 (53.85)	10 (21.74)
Location			0.007			0.015
Cardia	5 (15.63)	40 (36.36)		1 (7.69)	18 (39.13)
Body	6 (18.75)	34 (30.91)		4 (30.77)	19 (41.31)
Antrum	20 (62.50)	32 (29.09)		7 (53.85)	8 (17.39)
Whole	1 (3.12)	4 (3.64)		1 (7.69)	1 (2.17)
Clinical T stage			0.013			0.762
T3	13 (40.63)	73 (66.36)		7 (53.85)	27 (58.70)
T4	19 (59.37)	37 (33.64)		6 (46.15)	19 (41.30)
Clinical N stage			0.062			0.113
N-	17 (53.13)	37 (33.64)		10 (76.92)	22 (47.83)
N+	15 (46.87)	73 (66.36)		3 (23.08)	24 (52.17)
CA 72−4 level			0.290			0.187
Normal	24 (75.00)	93 (84.55)		7 (53.85)	34 (73.91)
Abnormal	8 (25.00)	17 (15.45)		6 (46.15)	12 (26.09)
CA 19−9 level			0.605			0.357
Normal	25 (78.13)	91 (82.73)		10 (76.92)	41 (89.13)
Abnormal	7 (21.87)	19 (17.27)		3 (23.08)	5 (10.87)
CEA level			0.443			1.00
Normal	25 (78.13)	92 (83.64)		11 (84.62)	40 (86.96)
Abnormal	7 (21.87)	18 (16.36)		2 (15.38)	6 (13.04)
Radiomics score *	0.91 (0.50, 1.22)	1.53 (1.22, 1.87)	< 0.001	0.85 (0.43, 1.12)	1.49 (0.94, 1.67)	< 0.001

Note: Except where indicated, data are number (%) of patients. MSI-H = microsatellite instability-high, MSS = microsatellite stability, CA 72 − 4 = carbohydrate antigen 72 − 4, CA 19 − 9 = carbohydrate antigen 19 − 9, CEA = carcinoembryonic antigen

* Data in parentheses are interquartile range