Development and Validation of Nomograms to Assess Risk Factors and Overall Survival Prediction for Lung Metastasis in Young Patients with Osteosarcoma: A SEER-Based Study

Table 3

Clinical characteristics of 114 osteosarcoma patients with LM.

	Training set (n = 82)	Validation set I (n = 32)	Validation set II (n = 32)	Χ^2/Z
Age, years				5.992	0.200
0–8	4 (4.88%)	6 (18.75%)	4 (12.50%)
9–16	53 (64.63%)	18 (56.25%)	21 (65.63%)
17–25	25 (30.49%)	8 (25.00%)	7 (21.88%)
Race				98.692	<0.001
Black	17 (20.73%)	5 (15.63%)	0 (0.00%)
White	57 (69.51%)	24 (75.00%)	0 (0.00%)
Other	8 (9.76%)	3 (9.38%)	32 (100.00%)
Sex				2.052	0.359
Female	39 (47.56%)	11 (34.38%)	12 (37.50%)
Male	43 (52.44%)	21 (65.63%)	20 (62.50%)
Primary site				3.272	0.774
Upper limb	13 (15.85%)	4 (12.50%)	4 (12.50%)
Lower limb	62 (75.61%)	25 (78.13%)	23 (71.88%)
Other	2 (2.44%)	2 (6.25%)	3 (9.38%)
Spine/pelvis	5 (6.10%)	1 (3.13%)	2 (6.25%)
Grade				1.308	0.520
II	1 (1.22%)	0 (0.00%)	0 (0.00%)
III	33 (40.24%)	10 (31.25%)	14 (43.75%)
IV	48 (58.54%)	22 (68.75%)	18 (56.25%)
Histological type				0.186	0.911
Osteosarcoma	61 (74.39%)	23 (71.88%)	25 (78.13%)
Chondroblastic osteosarcoma	14 (17.07%)	6 (18.75%)	3 (9.38%)
Other	5 (6.10%)	1 (3.13%)	1 (3.13%)
Central osteosarcoma	2 (2.44%)	2 (6.25%)	3 (9.38%)
T stage				5.985	0.428
T1	13 (15.85%)	4 (12.50%)	8 (25.00%)
T2	54 (65.85%)	25 (78.13%)	18 (56.25%)
T3	4 (4.88%)	2 (6.25%)	3 (9.38%)
TX	11 (13.41%)	1 (3.13%)	3 (9.38%)
N stage				1.094	0.895
N0	64 (78.05%)	23 (71.88%)	25 (78.13%)
N1	12 (14.63%)	5 (15.63%)	5 (15.63%)
NX	6 (7.32%)	4 (12.50%)	2 (6.25%)
Surgery				0.621	0.733
Yes	67 (81.71%)	28 (87.50%)	26 (81.25%)
No	15 (18.29%)	4 (12.50%)	6 (18.75%)
Chemotherapy				6.082	0.048
Yes	78 (95.12%)	30 (93.75%)	26 (81.25%)
No	4 (4.88%)	2 (6.25%)	6 (18.75%)
Radiotherapy				2.091	0.351
Yes	9 (10.98%)	2 (6.25%)	1 (3.13%)
No	73 (89.02%)	30 (93.75%)	31 (96.88%)
Tumor size, mm				1.219	0.544
0–100	30 (35.59%)	11 (34.38%)	15 (46.88%)
101–200	31 (37.80%)	14 (43.75%)	11 (34.38%)
>200	21 (25.61%)	7 (21.88%)	6 (18.75%)
Bone metastasis				1.974	0.373
No	69 (84.15%)	28 (87.50%)	24 (75.00%)
Yes	13 (15.85%)	4 (12.50%)	8 (25.00%)

LM: lung metastasis; validation set I: internal validation set; validation set II: external validation set.