Sites of Synchronous Distant Metastases, Prognosis, and Nomogram for Small Cell Lung Cancer Patients with Bone Metastasis: A Large Cohort Retrospective Study

Table 1

Demographic and clinical characteristics of SCLC patients with BM.

Variables	Total cohort		Training cohort		Validation cohort
	N = 6253		N = 4379		N = 1874
	n	%	n	%	n	%
Age
<66	2647	42.33	1824	41.65	823	43.92
66–79	2941	47.03	2082	47.55	859	45.84
>79	665	10.63	473	10.80	192	10.25
Race
Black	419	6.70	292	6.67	127	6.78
Others	267	4.27	191	4.36	76	4.06
White	5563	88.97	3894	88.92	1669	89.06
Unknown	4	0.06	2	0.05	2	0.11
Sex
Female	2779	44.44	1948	44.49	831	44.34
Male	3474	55.56	2431	55.51	1043	55.66
Primary site
Upper lobe	2857	45.69	2018	46.08	839	44.77
Middle lobe	219	3.50	158	3.61	61	3.26
Lower lobe	1260	20.15	865	19.75	395	21.08
Lung, NOS	1120	17.91	770	17.58	350	18.68
Others	797	12.75	568	12.97	229	12.22
Grade
I	7	0.11	6	0.14	1	0.05
II	8	0.13	6	0.14	2	0.11
III	457	7.31	317	7.24	140	7.47
IV	757	12.11	526	12.01	231	12.33
Unknown	5024	80.35	3524	80.48	1500	80.04
Laterality
Bilateral	89	1.42	58	1.32	31	1.65
Left	2519	40.28	1771	40.44	748	39.91
Right	3286	52.55	2297	52.45	989	52.77
Unknown	359	5.74	253	5.78	106	5.66
T stage
T1	434	6.94	292	6.67	142	7.58
T2	1145	18.31	801	18.29	344	18.36
T3	1094	17.50	744	16.99	350	18.68
T4	1932	30.90	1390	31.74	542	28.92
Unknown	1648	26.36	1152	26.31	496	26.47
N stage
N0	499	7.98	344	7.86	155	8.27
N1	306	4.89	227	5.18	79	4.22
N2	2962	47.37	2100	47.96	862	46.00
N3	1455	23.27	992	22.65	463	24.71
Unknown	1031	16.49	716	16.35	315	16.81
Radiotherapy
No	3836	61.35	2696	61.57	1140	60.83
Yes	2417	38.65	1683	38.43	734	39.17
Chemotherapy
No	1754	28.05	1220	27.86	534	28.50
Yes	4499	71.95	3159	72.14	1340	71.50
Surgery
No	6115	97.79	4279	97.72	1836	97.97
Yes	138	2.21	100	2.28	38	2.03
Brain metastasis
No	5063	80.97	3550	81.07	1513	80.74
Yes	1190	19.03	829	18.93	361	19.26
Liver metastasis
No	2723	43.55	1930	44.07	793	42.32
Yes	3530	56.45	2449	55.93	1081	57.68
Lung metastasis
No	4845	77.48	3380	77.19	1465	78.18
Yes	1408	22.52	999	22.81	409	21.83
Insurance status
Uninsured	203	3.24	140	3.20	63	3.36
Insured	6050	96.75	4239	96.80	1811	96.64
Marital status
Unmarried	2833	45.31	1982	45.26	851	45.41
Married	3420	54.69	2397	54.74	1023	54.59

SCLC, small cell lung cancer; BM, bone metastasis.