Prognostic factors in patients with bone metastasis of lung cancer after immune checkpoint inhibitors: A retrospective study

Table 1 Clinical characteristics of patients

Characteristic	Number
Age at bone metastasis	Median 70 (range: 42–87)
Sex
Male	29
Female	16
Histological type
Adenocarcinoma	37
Squamous	3
NOS	5
Bone metastases
Multiple	45
Single	0
Brain metastases
Yes	8
No	37
Adrenal metastasis
Yes	4
No	41
ECOG PS
1	29
2	13
3	3
4	0
Treatment before bone metastasis diagnosis
Yes	19
No	26
Chemotherapy before bone metastasis diagnosis
Yes	21
No	24
ICI use after bone metastasis diagnosis
Yes	28
No	17
Tumor proportion score
≥ 50%	15
< 50%	20
Not tested	10

ECOG PS: Eastern Cooperative Oncology Group performance status; NOS: Not otherwise specified; ICI: Immune checkpoint inhibitor.

Table 2 Types of immune checkpoint inhibitors used in patients (n = 28)

Type of immune checkpoint inhibitors	Number
Pembrolizumab	15
Nivolumab	2
Atezolizumab	3
Durvalumab	3
Ipilimumab	0
Pembrolizumab + atezolizumab	2
Pembrolizumab + durvalumab	1
Nivolumab + durvalumab	1
Nivolumab + ipilimumab	1

Table 3 Univariate analysis of overall survival in patients with bone metastasis of gene mutation-negative non-small cell lung cancer

Characteristic	n	Median OS	95%CI	P value
Age				0.51
≥ 70	23	14	7-not censored
< 70	22	19	10–54
Sex				0.72
Male	29	15	8–33
Female	16	16	8-not censored
Histological type				0.47
Adenocarcinoma	37	16	10–54
Others	8	14	1-not censored
Brain metastases				0.35
Yes	8	33	3–33
No	37	14	8–19
Adrenal metastasis				0.85
Yes	4	Not censored	4-not censored
No	41	16	8–33
ECOG PS				0.0079
≥ 2	16	8	3–33
≤ 1	29	19	13-not censored
Treatment before bone metastasis diagnosis				0.39
Yes	19	16	8-not censored
No	26	14	8–54
Chemotherapy before bone metastasis diagnosis				0.89
Yes	21	14	8–54
No	24	16	7–33
ICI use after bone metastasis diagnosis				0.031
Yes	28	22	8-not censored
No	17	13	5–16
Use of bone-modifying agent after bone metastasis diagnosis				0.027
Yes	36	16	12–54
No	9	5	2–33
Albumin				0.63
> 3.5	25	16	10-not censored
≤ 3.5	20	16	5–54
C-reactive protein				0.72
≥ 0.4	33	16	7–33
< 0.4	12	15	8-not censored
Lactate dehydrogenase				0.83
≥ 225	25	16	5–33
< 225	20	15	8–54
White blood cells				0.22
> 8500	20	14	5–22
≤ 8500	25	16	10–54
Neutrophil-to-lymphocyte ratio				0.47
≥ 5.0	21	16	8–33
< 5.0	24	15	8-not censored
Platelet-to-lymphocyte ratio				0.93
≥ 185	35	16	10–33
< 185	10	15	3–54

OS: Overall survival; ECOG PS: Eastern Cooperative Oncology Group performance status; ICIs: Immune checkpoint inhibitors.

Table 4 Multivariate analysis of overall survival in patients with bone metastasis of gene mutation-negative non-small cell lung cancer

	Characteristic	HR	95%CI	P value
Use of ICIs after bone metastasis diagnosis	Yes	0.35	0.14–0.86	0.023
Use of bone-modifying agent after bone metastasis diagnosis	Yes	0.43	0.16–1.2	0.12
ECOG PS	≤ 1	0.5	0.20–1.3	0.14

HR: Hazard ratio; ECOG PS: Eastern Cooperative Oncology Group performance status; ICIs: Immune checkpoint inhibitors.

Table 5 Univariate analysis following the division of patients into three groups based on tumor proportion score and immune checkpoint inhibitors use

	n	Median OS	95%CI	P value
TPS ≥ 50% and ICI use	12	54	3-not censored	0.079
TPS ≤ 49% or not tested and ICI use	16	19	8-not censored
No use of ICI	17	13	5–16

OS: Overall survival; TPS: Tumor proportion score; ICIs: Immune checkpoint inhibitors.