Magnetic resonance imaging-based lymph node radiomics for predicting the metastasis of evaluable lymph nodes in rectal cancer

Table 1 Demographics of training and validation set

Characteristic	All patients	Training set	Validation set	P value
	n = 144	n = 100	n = 44
Age in yr	59 ± 10	59 ± 9	60 ± 10	0.514
Sex				0.805
Male	97 (67.4)	68 (68.0)	29 (65.9)
Female	47 (32.6)	32 (32.0)	15 (34.1)
CEA in ng/mL1		4.0 (2.4, 7.8)	3.8 (2.3, 9.3)	0.787
Location				0.165
Upper	31 (21.5)	22 (22.0)	9 (20.5)
Middle	66 (45.8)	41 (41.0)	25 (56.8)
Lower	47 (32.6)	37 (37.0)	10 (22.7)
Surgical approach				0.489
Dixon	120 (83.3)	82 (82.0)	38 (86.4)
Miles	21 (14.6)	15 (15.0)	6 (13.6)
Hartman	3 (2.1)	3 (3.0)	0 (0.0)
Surgical specimen histological type				0.877
Ulcerative	96 (66.7)	68 (68.0)	28 (63.6)
Infiltrative	6 (4.2)	4 (4.0)	2 (4.5)
Nodular	42 (29.2)	28 (28.0)	14 (31.8)
Differentiation				0.689
Well	8 (5.6)	5 (5.0)	3 (6.8)
Moderate	86 (59.7)	62 (62.0)	24 (54.5)
Poor	50 (34.7)	33 (33.0)	17 (38.6)
Pathological T stage				0.579
T1	7 (4.9)	4 (4.0)	3 (6.8)
T2	39 (27.1)	29 (29.0)	10 (22.7)
T3	84 (58.3)	59 (59.0)	25 (56.8)
T4	14 (9.7)	8 (8.0)	6 (13.6)
Pathological N status				0.293
Positive	53 (36.8)	34 (34.0)	19 (43.2)
Negative	91 (63.2)	66 (66.0)	25 (56.8)

¹Data are n (%) or median (IQR).

CEA: Carcinoembryonic antigen.