Prognostic value of systemic immune-inflammation index in patients with gastric cancer treated with immune checkpoint inhibitors

Table 1 Comparison of baseline characteristics of gastric cancer patients in the poor prognosis and good prognosis groups, n (%)/mean ± SD

Parameters	Good prognosis group (n = 143)	Poor prognosis group (n = 95)	t/χ²	P value
Gender			0.163	0.687
Female	52 (36.36)	37 (38.95)
Male	91 (63.64)	58 (61.05)
Age (years)	62.34 ± 4.15	63.28 ± 3.87	1.756	0.080
Body mass index (kg/m2)	22.15 ± 3.02	21.89 ± 2.24	0.756	0.450
Eastern Cooperative Oncology Group			12.643	0.002
0	72 (50.35)	38 (40.00)
1	58 (40.56)	32 (33.68)
2	13 (9.09)	25 (26.32)
Clinical staging			10.659	0.001
IV	91 (63.64)	79 (83.16)
III	52 (36.36)	16 (16.84)
Number of distant metastases			8.636	0.003
≥ 2	61 (42.66)	59 (62.11)
< 2	82 (57.34)	36 (37.89)
Previous gastric cancer resection surgery			0.692	0.406
Yes	65 (45.45)	38 (40.00)
No	78 (54.55)	57 (60.00)
Treatment regimen			8.325	0.004
Combination therapy	83 (58.04)	37 (38.95)
Monotherapy	60 (41.96)	58 (61.05)
Programmed cell death ligand 1 overexpression (combined positive score)			8.692	0.003
≥ 1	80 (55.94)	71 (74.74)
< 1	63 (44.06)	24 (25.26)

Table 2 Comparison of laboratory indicators of gastric cancer patients in the poor prognosis and good prognosis groups, mean ± SD

Parameters	Good prognosis group (n = 143)	Poor prognosis group (n = 95)	t value	P value
Platelet count (× 109/L)	207.46 ± 68.33	230.71 ± 74.25	2.482	0.014
Neutrophil count (× 109/L)	3.91 ± 1.12	4.32 ± 1.37	2.442	0.016
Lymphocyte count (× 109/L)	1.61 ± 0.38	1.48 ± 0.41	2.398	0.017
Systemic immune-inflammation index	503.83 ± 138.74	673.42 ± 152.91	8.864	< 0.001

Table 3 Multivariate logistic regression analysis of the risk factors for progressive disease within six months in gastric cancer patients receiving immune checkpoint inhibitors

Parameters	Coefficient	SE	Wald Stat	P value	OR	OR 95%CI lower	OR 95%CI upper
Eastern Cooperative Oncology Group (2)	0.554	0.237	2.337	0.019	1.740	1.094	2.770
Clinical staging (IV)	0.900	0.400	2.247	0.025	2.459	1.122	5.391
Number of distant metastases (≥ 2)	0.684	0.342	1.999	0.046	1.982	1.014	3.875
Treatment regimen (combination therapy)	-0.721	0.342	-2.108	0.035	0.486	0.249	0.951
Programmed cell death ligand 1 overexpression (combined positive score ≥ 1)	0.804	0.367	2.192	0.028	2.234	1.089	4.586
Systemic immune-inflammation index	0.006	0.001	5.566	< 0.001	1.006	1.004	1.009

OR: Odds ratio.

Table 4 Receiver operating characteristic analysis of the risk factors for progressive disease within six months in gastric cancer patients receiving immune checkpoint inhibitors

Parameters	Best threshold	Sensitivities	Specificities	Area under the curve	Youden index	F1 score
Eastern Cooperative Oncology Group (2)	0.500	0.263	0.909	0.590	0.172	0.376
Clinical staging (IV)	0.500	0.832	0.364	0.598	0.196	0.596
Number of distant metastases (≥ 2)	0.500	0.621	0.573	0.597	0.194	0.549
Treatment regimen (combination therapy)	0.500	0.611	0.580	0.595	0.191	0.344
Programmed cell death ligand 1 overexpression (combined positive score ≥ 1)	0.500	0.747	0.441	0.594	0.188	0.577
Systemic immune-inflammation index	593.995	0.705	0.727	0.788	0.432	0.667

Table 5 Comparison of baseline information of gastric cancer patients in the high and low systemic immune-inflammation index groups, n (%)/mean ± SD

Parameters	Low SII group (n = 128)	High SII group (n = 110)	t/χ²	P value
Gender			0.054	0.816
Female	47 (36.72)	42 (38.18)
Male	81 (63.28)	68 (61.82)
Age (years)	62.45 ± 3.97	63.02 ± 4.05	1.101	0.272
Body mass index (kg/m2)	22.18 ± 3.01	21.87 ± 3.08	0.790	0.430
Eastern Cooperative Oncology Group			8.111	0.017
0	67 (52.34)	43 (39.09)
1	48 (37.50)	42 (38.18)
2	13 (10.16)	25 (22.73)
Clinical staging			7.363	0.007
IV	82 (64.06)	88 (80.00)
III	46 (35.94)	22 (20.00)
Number of distant metastases			6.151	0.013
≥ 2	55 (42.97)	65 (59.09)
< 2	73 (57.03)	45 (40.91)
Previous gastric cancer resection surgery			1.460	0.227
Yes	60 (46.88)	43 (39.09)
No	68 (53.12)	67 (60.91)
Treatment regimen			0.014	0.904
Combination therapy	65 (50.78)	55 (50.00)
Monotherapy	63 (49.22)	55 (50.00)
Programmed cell death ligand 1 overexpression (combined positive score)			0.045	0.831
≥ 1	82 (64.06)	69 (62.73)
< 1	46 (35.94)	41 (37.27)

SII: Systemic immune-inflammation index.

Table 6 Comparison of therapeutic response of gastric cancer patients in the high and low systemic immune-inflammation index groups, n (%)

Parameters	Low SII group (n = 128)	High SII group (n = 110)	χ²	P value
Disease control rate (PR + SD)	89 (69.53)	54 (49.09)	10.306	0.001
PR	16 (12.50)	7 (6.36)
SD	73 (57.03)	47 (42.73)
Progressive disease	39 (30.47)	56 (50.91)

PR: Partial response; SD: Stable disease; SII: Systemic immune-inflammation index.

Table 7 Multivariate Cox proportional hazards regression analysis of risk factors affecting progression-free survival in gastric cancer patients treated with immune checkpoint inhibitors

Parameters	P value	Hazard ratio	95%CI
Eastern Cooperative Oncology Group (2)	0.018	1.642	1.088-2.478
Clinical staging (IV)	0.001	2.149	1.361-3.394
Number of distant metastases (≥ 2)	0.032	1.593	1.042-2.435
Treatment regimen (combination therapy)	0.076	0.712	0.491-1.032
Programmed cell death ligand 1 overexpression (combined positive score ≥ 1)	0.124	0.803	0.608-1.061
High systemic immune-inflammation index (≥ 593.995)	0.005	1.896	1.214-2.961