TABLE 1.

Patients characteristics

Characteristic		No. of patients	%
Age, years	<70	188	51.1
	≥70	180	48.9
Sex	Male	242	65.8
	Female	126	34.2
ECOG‐PS	0–1	158	42.9
	2	103	28.0
	3–4	107	29.1
Histology	Adenocarcinoma	247	67.1
	Squamous cell carcinoma	53	14.4
	Small cell carcinoma	39	10.6
	Other	29	7.9
Smoking history	Yes	228	72.2
	No	88	27.8
Timing of RT	De novo	136	37.0
	Relapse or appearance	232	63.0
Metastases on internal organs	Yes	292	79.3
	Single	130	44.0
	Multiple	162	35.3
	No	76	20.7
No. of bone metastatic lesions	1	90	24.5
	2–3	43	11.7
	≥4	235	63.9
Bone metastatic sites	Only vertebral	85	23.1
	Only non‐vertebral	62	16.8
	Others	221	60.0
Neurological symptom	Yes	74	20.1
	No	294	79.9
Pathological fracture	Yes	64	17.4
	No	304	82.6
RT course	Shorter course RT	83	22.6
	Longer course RT	285	77.4
Pre‐RT ATs	Yes	189	51.4
	TKIs	49	13.3
	ICIs	32	8.7
	TKIs + ICIs	2	0.5
	Other ATs	106	28.8
	No	179	48.6
Post‐RT ATs	Yes	194	52.7
	TKIs	87	23.6
	ICIs	31	8.4
	Other ATs	76	20.7
	No	174	47.3
Pre‐RT laboratory data, median [range]	CRP (mg/dL)	1.58 [0.01–110.7]
	LDH (U/L)	257 [119–10 573]
	Albumin (g/dL)	3.6 [1.7–4.9]
	Platelet (×104/μL)	23.2 [2.7–147.6]
	Ca (mg/dL)	9.1 [5.8–22.5]
	T‐Bil (mg/dL)	0.46 [0.15–28.0]

Abbreviations: ATs, antineoplastic agents; Ca, calcium; CRP, C‐reactive protein; de novo, bone metastases eligible for palliative RT at presentation; ECOG PS, Eastern Cooperative Oncology Group Performance Status; ICIs, immune checkpoint inhibitors; LDH, lactate dehydrogenase; relapse or appearance, bone metastases not eligible for palliative RT at presentation, or appeared after definitive treatment; RT, radiotherapy; T‐Bil, total bilirubin; TKIs, tyrosine kinase inhibitors.