Deep learning radiomics-based prediction model of metachronous distant metastasis following curative resection for retroperitoneal leiomyosarcoma: a bicentric study

Table 1 Clinical characteristics of patients in the training and external validation cohorts

Variable	Training Cohort (n = 121)			External Validation Cohort (n = 58)			Training vs. Validation
Variable	non-MDM (N = 73)	MDM (N = 48)	P value	non-MDM (N = 43)	MDM (N = 15)	P value	P value
Age (years, median [IQR])	59 [50, 64]	60 [48.2, 66.3]	0.693	56.0 [47.5, 62]	66.0 [38.5,69.5]	0.282	0.81
Gender (n, %)			0.158			0.764	0.959
Male	33 (45.2)	28 (58.3)		21 (48.8)	8 (53.3)
Female	40 (54.8)	20 (41.7)		22 (51.2)	7 (46.7)
Ki-67 index (%, median [IQR])	10 [5, 30]	20 [5, 40]	0.454	10.0 [5, 30]	10.0 [5, 40]	0.596	0.43
Tumor size (n, %)			< 0.001			0.885	0.231
≤ 10 cm	41 (56.2)	6 (12.5)		21 (48.8)	7 (46.7)
> 10 cm	32 (43.8)	42 (87.5)		22 (51.2)	8 (53.3)
Clinical N stage (n, %)			0.455			0.272	0.975
N0	63 (86.3)	39 (81.2)		35 (81.4)	14 (93.3)
N1	10 (13.7)	9 (18.8)		8 (18.6)	1 (6.7)
Cystic spaces or necrosis (n, %)			0.338			0.364	0.36
Not Present	34 (46.6)	23 (48.0)		20 (46.6)	10 (66.7)
Present	39 (53.4)	25 (52.0)		23 (53.4)	5 (33.3)
Degree of enhancement (n, %)			0.332			0.642	0.683
Higher than muscle	64 (87.7)	39 (81.2)		35 (81.4)	13 (86.7)
Slightly below or equal to muscle	9 (12.3)	9 (18.8)		8 (18.6)	2 (13.3)
Enhancement pattern (n, %)			0.037			0.587	0.112
Heterogeneous	63 (86.3)	34 (70.8)		38 (88.4)	14 (93.3)
Homogeneous	10 (13.7)	14 (29.2)		5 (11.6)	1 (6.7)
Tumor contours (n, %)			0.712			0.07	0.862
Smooth	39 (53.4)	24 (50)		26 (60.5)	5 (33.3)
Irregular	34 (46.6)	24 (50)		17 (39.5)	10 (66.7)
Adjacent organ involvement (n, %)			0.224			0.16	0.903
Not Present	60 (82.2)	35 (72.9)		36 (83.7)	10 (66.7)
Present	13 (17.8)	13 (27.1)		7 (16.3)	5 (33.3)

Note: The tumor size and N stage was referred to the 8th edition of the American Joint Committee on Cancer (AJCC) staging system
Abbreviations: MDM, metachronous distant metastasis; IQR, interquartile

ISSN: 1470-7330