Baseline clinicopathological characteristics
Patients with GC or EC who received PD-1 inhibitor-based combination therapy (n = 203) were enrolled in the study. In the training cohort (n = 87), median age at ICI initiation was 67 years. 27 patients had high blood pressure (HBP), and 10 had diabetes mellitus (DM). Tumor histology types were adenocarcinoma (n = 45) and squamous carcinoma (n = 42), with 42 patients having EC and 45 GC. Distant metastases were detected in 69 patients and 25 patients were positive for PD-L1 expression (CPS ≥ 1%). Antibiotic (n = 14) and corticosteriods (n = 30) use were recorded during or before ICI treatment. ICI treatment was initiated in the 1st (n = 58), 2nd (n = 23), or 3rd to 4th (n = 6) lines. Overall incidence of dermatologic toxicities was 33.3% (29/87) in the training cohort. Measured laboratory variables included ALC, AMC, and ANC, among others. Baseline clinicopathlogical characteristics of the validation cohort were also presented in Table 1. All these characteristics were comparable between the two cohorts (P > 0.05). The baseline clinicopathlogical characteristics of the test cohort were presented in the supplementary Table 1.
Table 1. Baseline clinicopathological characteristics of patients in the training and validation cohort
|
Characteristics
|
Training cohort (n=87)
|
Validation cohort (n=64)
|
P-value
|
Demographic characteristics
|
|
|
|
Age at ICI initiation (years)
|
67 (27-86)
|
65 (45-89)
|
0.630
|
Sex
|
|
|
|
Male
|
67 (77.0%)
|
50 (78.1%)
|
0.871
|
Female
|
20 (23.0%)
|
14 (21.9%)
|
|
ECOG PS at ICI initiation
|
|
|
|
0
|
4 (4.6%)
|
3 (4.7%)
|
0.993
|
1
|
34 (39.1%)
|
25 (39.1%)
|
|
2
|
49 (56.3%)
|
36 (56.3%)
|
|
HBP
|
|
|
|
Yes
|
27 (31.0%)
|
12 (18.8%)
|
0.088
|
No
|
60 (69.0%)
|
52 (81.3%)
|
|
DM
|
|
|
|
Yes
|
10 (11.5%)
|
6 (9.4%)
|
0.676
|
No
|
77 (88.5%)
|
58 (90.6%)
|
|
Tumor variables
|
|
|
|
Histology
|
|
|
|
Adenocarcinoma
|
45 (51.7%)
|
33 (51.6%)
|
0.984
|
Squamous carcinoma
|
42 (48.3%)
|
31 (48.4%)
|
|
Tumor type
|
|
|
|
Esophageal cancer
|
42 (48.3%)
|
31 (48.4%)
|
0.984
|
Gastric cancer
|
45 (51.7%)
|
33 (51.6%)
|
|
Distant metastasis
|
|
|
|
Yes
|
69 (79.3%)
|
48 (75.0%)
|
0.531
|
No
|
18 (20.7%)
|
16 (25.0%)
|
|
PD-L1 expression (CPS)
|
|
|
|
>1%
|
25 (28.7%)
|
27 (42.2%)
|
0.215
|
<1%
|
37 (42.5%)
|
25 (39.1%)
|
|
Missing
|
25 (28.7%)
|
12 (18.8%)
|
|
ICI treatment variables
|
|
|
|
Antibiotic use
|
|
|
|
Yes
|
14 (16.1%)
|
12 (18.8%)
|
0.669
|
No
|
73 (83.9%)
|
52 (81.3%)
|
|
Corticosteroids use
|
|
|
|
Yes
|
30 (34.5%)
|
23 (35.9%)
|
0.853
|
No
|
57 (65.5%)
|
41 (64.1%)
|
|
ICI treatment line
|
|
|
|
1st-line
|
58 (66.7%)
|
53 (82.8%)
|
0.113
|
2nd-line
|
23 (26.4%)
|
7 (10.9%)
|
|
3rd, or 4th-line
|
6 (6.9%)
|
4 (6.3%)
|
|
Dermatologic toxicities
|
|
|
|
Yes
|
29 (33.3%)
|
20 (31.3%)
|
0.787
|
No
|
58 (66.7%)
|
44 (68.8%)
|
|
Laboratory variables
|
|
|
|
ALC (*10^9/L)
|
1.18 (0.33-4.53)
|
1.10 (0.19-2.46)
|
0.121
|
AMC (*10^9/L)
|
0.44 (0.09-1.89)
|
0.46 (0.14-1.10)
|
0.920
|
ANC (*10^9/L)
|
3.12 (1.02-15.04)
|
3.58 (1.65-15.50)
|
0.920
|
HGB (g/L)
|
114 (54-167)
|
119 (72-150)
|
0.238
|
LDH (IU/L)
|
169 (94-3187)
|
170 (21-1540)
|
0.291
|
CEA (ng/mL)
|
3.20 (0.27-645.20)
|
2.27 (0.22-481.70)
|
0.432
|
CA 19-9 (U/mL)
|
16.28 (0.01-883.10)
|
7.44 (0.69-1000)
|
0.111
|
CD3+
|
656 (318-2760)
|
784 (296-2664)
|
0.078
|
CD3+CD4+CD8-
|
339 (104-1592)
|
418 (137-1572)
|
0.100
|
CD3+CD4-CD8+
|
296 (114-1024)
|
352 (124-1120)
|
0.176
|
CD4+/CD8+ ratio
|
1.06 (0.25-5.60)
|
1.29 (0.46-3.00)
|
0.904
|
Abbreviations: ICI, immune checkpoint inhibitors, HBP, high blood pressure, DM, diabetes mellitus, ALC, absolute lymphocyte count, AMC, absolute monocyte count, ANC, absolute neutrophil count, HGB, hemoglobin, LDH, lactate dehydrogenase, CEA, Carcinoma Embryonic Antigen, CA19-9, carbohydrate antigen 19-9.
Prognostic factors for OS
Univariate analysis identified ECOG PS at ICI initiation, distant metastasis, PD-L1 expression, antibiotic use, corticosteroids use, dermatologic toxicities, NLR, LMR, and CD4+/CD8+ ratio as potentially correlated with patients’ prognosis (P < 0.05). These factors were then incorporated into a multivariate Cox regression model for further analysis. The results demonstrated that ECOG PS at ICI initiation (hazard ratio (HR), 2.698, 95% confidence interval (CI), 1.189 - 6.122), PD-L1 expression (HR, 0.439, 95% CI, 0.203 - 0.949), antibiotic use (HR, 3.301, 95%CI, 1.416 - 7.696), and CD4+/CD8+ ratio (HR, 1.636, 95% CI, 1.129 - 2.370) were independent prognostic variables (P < 0.05, Table 2). The prognostic value of these factors was verified by analysis of validation group and test group data. Among them, ECOG PS at ICI initiation (HR, 2.519, 95% CI, 1.036-6.125, P = 0.042), antibiotic use (HR, 3.948, 95% CI, 1.044-14.929, P = 0.043), and CD4+/CD8+ ratio (HR, 2.170, 95% CI, 1.119-4.209, P = 0.022) remained as independent prognostic factors in the validation cohort (Table 3).
Table 2. Univariate and multivariate analysis of prognostic factors in the training cohort
|
|
Univariate analysis
|
Multivariate analysis
|
Characteristics
|
HR
|
95%CI
|
P-value
|
HR
|
95%CI
|
P-value
|
Age
|
|
|
|
|
|
|
<65
|
1.014
|
0.599-1.718
|
0.958
|
|
|
|
>65
|
Reference
|
|
|
|
|
|
Sex
|
|
|
|
|
|
|
Male
|
1.552
|
0.835-2.885
|
0.165
|
|
|
|
Female
|
Reference
|
|
|
|
|
|
ECOG PS at ICI initiation
|
|
|
|
|
|
|
2
|
2.163
|
1.253-3.735
|
0.006
|
2.698
|
1.189-6.122
|
0.018
|
0-1
|
Reference
|
|
|
Reference
|
|
|
HBP
|
|
|
|
|
|
|
Yes
|
0.895
|
0.512-1.564
|
0.697
|
|
|
|
No
|
Reference
|
|
|
|
|
|
DM
|
|
|
|
|
|
|
Yes
|
0.493
|
0.231-1.053
|
0.068
|
|
|
|
No
|
Reference
|
|
|
|
|
|
Tumor type
|
|
|
|
|
|
|
Esophageal cancer
|
1.345
|
0.807-2.243
|
0.255
|
|
|
|
Gastric cancer
|
Reference
|
|
|
|
|
|
Distant metastases
|
|
|
|
|
|
|
Yes
|
2.057
|
1.076-3.933
|
0.029
|
1.238
|
0.405-3.788
|
0.708
|
No
|
Reference
|
|
|
Reference
|
|
|
PD-L1 expression
|
|
|
|
|
|
|
>1%
|
0.424
|
0.217-0.831
|
0.012
|
0.439
|
0.203-0.949
|
0.036
|
<1%
|
Reference
|
|
|
Reference
|
|
|
Antibiotic use
|
|
|
|
|
|
|
Yes
|
2.119
|
1.139-3.943
|
0.018
|
3.301
|
1.416-7.696
|
0.006
|
No
|
Reference
|
|
|
Reference
|
|
|
Corticosteroids use
|
|
|
|
|
|
|
Yes
|
1.741
|
1.008-3.006
|
0.047
|
2.120
|
0.957-4.696
|
0.064
|
No
|
Reference
|
|
|
Reference
|
|
|
Dermatologic toxicities
|
|
|
|
|
|
|
Yes
|
0.399
|
0.222-0.719
|
0.002
|
0.745
|
0.328-1.690
|
0.481
|
No
|
Reference
|
|
|
Reference
|
|
|
HGB (g/L)
|
1.000
|
0.988-1.012
|
0.987
|
|
|
|
NLR
|
1.074
|
1.023-1.128
|
0.004
|
0.969
|
0.900-1.043
|
0.404
|
LMR
|
0.764
|
0.624-0.935
|
0.009
|
0.820
|
0.622-1.081
|
0.160
|
LDH (IU/L)
|
1.000
|
1.000-1.001
|
0.932
|
|
|
|
CEA (ng/ml)
|
1.001
|
0.998-1.004
|
0.499
|
|
|
|
CA19-9 (U/mL)
|
1.000
|
0.998-1.002
|
0.958
|
|
|
|
CD3+
|
1.000
|
0.999-1.001
|
0.722
|
|
|
|
CD3+CD4+CD8-
|
1.000
|
0.999-1.001
|
0.388
|
|
|
|
CD3+CD4-CD8+
|
0.998
|
0.997-1.000
|
0.068
|
|
|
|
CD4+/CD8+ ratio
|
1.423
|
1.140-1.775
|
0.002
|
1.636
|
1.129-2.370
|
0.009
|
Abbreviations: ICI, immune checkpoint inhibitors, HBP, high blood pressure, DM, diabetes mellitus, NLR, neutrophil-to-lymphocyte ratio, LMR, lymphocyte-to-monocyte ratio, HGB, hemoglobin, LDH, lactate dehydrogenase, CEA, Carcinoma Embryonic Antigen, CA19-9, carbohydrate antigen 19-9.
Table 3. Multivariate analysis of OS in the validation cohort
|
|
Multivariate analysis
|
Characteristics
|
HR
|
95%CI
|
P-value
|
ECOG PS at ICI initiation
|
|
|
|
2
|
2.519
|
1.036-6.125
|
0.042
|
0-1
|
Reference
|
|
|
Distant metastases
|
|
|
|
Yes
|
1.655
|
0.507-5.409
|
0.404
|
No
|
Reference
|
|
|
PD-L1 expression
|
|
|
|
>1%
|
0.609
|
0.245-1.516
|
0.287
|
<1%
|
Reference
|
|
|
Antibiotic use
|
|
|
|
Yes
|
3.948
|
1.044-14.929
|
0.043
|
No
|
Reference
|
|
|
Corticosteroids use
|
|
|
|
Yes
|
1.590
|
0.608-4.155
|
0.344
|
No
|
Reference
|
|
|
Dermatologic toxicities
|
|
|
|
Yes
|
0.520
|
0.154-1.755
|
0.292
|
No
|
Reference
|
|
|
NLR
|
1.018
|
0.897-1.154
|
0.787
|
LMR
|
0.623
|
0.356-1.091
|
0.098
|
CD4+/CD8+ ratio
|
2.170
|
1.119-4.209
|
0.022
|
Abbreviations: ICI, immune checkpoint inhibitors, NLR, neutrophil-to-lymphocyte ratio, LMR, lymphocyte-to-monocyte ratio.
Establishment and validation of the a nomogram
A nomogram was constructed based on the prognostic factors identified by multivariate analysis in the training cohort (Figure 1). The nomogram could predict median survival time and survival probabilities at 6, 12, and 24 months. Harrell’s C-index value of the nomogram was 0.767. After adjustment by bootstrapping with 1,000 re-samples, calibration plots, which showed concordance between actual and ideal survival predictions, were demonstrated for 6- and 12-month survival (Figure 2). Further, a nomogram comprising the same variables also showed a good discriminatory ability in the validation cohort (C-index, 0.791) and test cohort (C-index, 0.784).
Subgroup analysis for CD4+/CD8+ ratio
In the subgroup analysis, CD4+/CD8+ ratio was significantly correlated with OS in patients stratified by age, sex, antibiotic use, and ICI treatment line. However, no correlations with OS were detected in patients without distant metastasis or with ECOG PS = 0-1 (Figure 3).
Value of CD4+/CD8+ ratio for predicting immunotherapy efficacy
Patients were divided into two groups, according to a CD4+/CD8+ ratio cut-off value of 1.10. In the training cohort, Kaplan-Meier analysis showed that the median OS in patients with a CD4+/CD8+ ratio > 1.10 was 6.2 months, which was significantly shorter than that of patients with CD4+/CD8+ ratio < 1.10 (17.3 months, 95%CI 12.8-21.8) (P < 0.001, Figure 4A). For patients with EC, median OS was 7.6 (95%CI 3.7-11.5) months in those with a CD4+/CD8+ ratio > 1.10 and 16.8 (95%CI 10.6-23.0) months in patients with CD4+/CD8+ ratio < 1.10 (P = 0.002, Figure 4B). For patients with GC, the median OS was 5.2 (95%CI 0.7-8.7) and 17.5 (95%CI 10.2-24.8) months in those with CD4+/CD8+ ratio > 1.10 and < 1.10, respectively (P < 0.001, Figure 4C). Similar results were also observed in the validation cohort (Figure 4D-F).
Pie charts and histograms were constructed to illustrate the efficacy of immunotherapy in the training cohort. We found that patients with CD4+/CD8+ ratio < 1.10 had almost double the likelihood of good response to ICI treatment compared with those with ratio > 1.10 (CR 4.2% vs. 2.6%, PR, 39.6% vs. 20.5%, Figure 5A-B). On the contrast, patients with CD4+/CD8+ ratio > 1.10 had much higher probability of PD than those with ratio < 1.10 (41.0% vs. 27.1%). Overall, patients with CD4+/CD8+ ratio < 1.10 had superior objective response rate (ORR, 43.8% vs. 23.1%) and disease control rate (DCR, 72.9% vs. 59.0%) than those with CD4+/CD8+ ratio > 1.10, suggesting a significant difference in the efficacy of immunotherapy (Figure 5C).
Correlations between CD4+/CD8+ ratio and clinicopathological features
Next, we investigated correlations between CD4+/CD8+ ratio and other clinicopathological features in both the training and validation cohorts (Table 4). Age (P = 0.002), sex (P = 0.042), distant metastasis (P = 0.001), antibiotic use (P = 0.029), and dermatologic toxicities (P < 0.001) were found to be significantly correlated with CD4+/CD8+ ratio in the training cohort (Table 4). Significant correlations between CD4+/CD8+ ratio and these factors, other than distant metastasis (P = 0.465), were further confirmed in the validation cohort. ECOG PS at ICI initiation (P = 0.080) and ICI treatment line (P = 0.067) were also potentially correlated with CD4+/CD8+ ratio in the training cohort.
Table 4. Correlations between CD4+/CD8+ ratio and clinicopathological variables
|
|
Training cohort
|
Validation cohort
|
Characteristics
|
CD4+/CD8+ < 1.10
|
CD4+/CD8+ > 1.10
|
P-value
|
CD4+/CD8+ < 1.10
|
CD4+/CD8+ > 1.10
|
P-value
|
Age
|
|
|
|
|
|
|
<65
|
24 (77.4%)
|
7 (22.6%)
|
0.002
|
17 (53.1%)
|
15 (46.9%)
|
0.076
|
>65
|
24 (42.9%)
|
32 (57.1%)
|
10 (31.3%)
|
22 (68.8%)
|
Sex
|
|
|
|
|
|
|
Male
|
33 (49.3%)
|
34 (50.7%)
|
0.042
|
18 (36.0%)
|
32 (64.0%)
|
0.058
|
Female
|
15 (75.0%)
|
5 (25.0%)
|
9 (64.3%)
|
5 (35.7%)
|
ECOG PS at ICI initiation
|
|
|
|
|
|
|
0-1
|
25 (65.8%)
|
13 (34.2%)
|
0.080
|
15 (53.6%)
|
13 (46.4%)
|
0.104
|
2
|
23 (46.9%)
|
26 (53.1%)
|
12 (33.3%)
|
24 (66.7%)
|
HBP
|
|
|
|
|
|
|
Yes
|
16 (59.3%)
|
11 (40.7%)
|
0.607
|
3 (25.0%)
|
9 (75.0%)
|
0.181
|
No
|
32 (53.3%)
|
28 (46.7%)
|
24 (46.2%)
|
28 (53.8%)
|
DM
|
|
|
|
|
|
|
Yes
|
4 (40.0%)
|
6 (60.0%)
|
0.333
|
2 (33.3%)
|
4 (66.7%)
|
0.645
|
No
|
44 (57.1%)
|
33 (42.9%)
|
25 (43.1%)
|
33 (56.9%)
|
Tumor type
|
|
|
|
|
|
|
Esophageal cancer
|
25 (59.5%)
|
17 (40.5%)
|
0.430
|
10 (32.3%)
|
21 (67.7%)
|
0.119
|
Gastric cancer
|
23 (51.1%)
|
22 (48.9%)
|
17 (51.5%)
|
16 (48.%)
|
Distant metastases
|
|
|
|
|
|
|
Yes
|
32 (46.4%)
|
37 (53.6%)
|
0.001
|
19 (39.6%)
|
29 (60.4%)
|
0.465
|
No
|
16 (88.9%)
|
2 (11.1%)
|
8 (50.0%)
|
8 (50.0%)
|
PD-L1 expression
|
|
|
|
|
|
|
>1%
|
13 (52.0%)
|
12 (48.0%)
|
0.796
|
14 (51.9%)
|
13 (48.1%)
|
0.080
|
<1%
|
18 (48.6%)
|
19 (51.4%)
|
7 (28.0%)
|
18 (72.0%)
|
Antibiotic use
|
|
|
|
|
|
|
Yes
|
4 (28.6%)
|
10 (71.4%)
|
0.029
|
1 (8.3%)
|
11 (91.7%)
|
0.008
|
No
|
44 (60.3%)
|
29 (39.7%)
|
26 (50.0%)
|
26 (50.0%)
|
Corticosteroids use
|
|
|
|
|
|
|
Yes
|
14 (46.7%)
|
16 (53.3%)
|
0.247
|
7 (30.4%)
|
16 (69.6%)
|
0.154
|
No
|
34 (59.6%)
|
23 (40.4%)
|
20 (48.8%)
|
21 (51.2%)
|
Dermatologic toxicities
|
|
|
|
|
|
|
Yes
|
24 (82.8%)
|
5 (17.2%)
|
<0.001
|
13 (65.0%)
|
7 (35.0%)
|
0.013
|
No
|
24 (41.4%)
|
34 (58.6%)
|
14 (31.8%)
|
30 (68.2%)
|
ICI treatment line
|
|
|
|
|
|
|
1st-line
|
28 (48.3%)
|
30 (51.7%)
|
0.067
|
17 (32.1%)
|
36 (67.9%)
|
<0.001
|
>2nd-line
|
20 (69.0%)
|
9 (31.0%)
|
10 (90.9%)
|
1 (9.1%)
|
Abbreviations: ICI, immune checkpoint inhibitors, HBP, high blood pressure, DM, diabetes mellitus.
Value of CD4+/CD8+ ratio in predicting dermatologic toxicities
Dermatologic toxicities, which mainly manifest in the form of pruritus and rash, appear to be one of the most prevalent immnue-related adverse events. Prediction and early recognition of dermatologic toxicities are of significant importance in mitigating the severity of the lesions. Although dermatologic toxicities is not an independent prognostic factor in multivariate Cox regression model, Kaplan-meier analysis showed that it is significantly correlated with OS. The median OS in patients without dermatologic toxicities was 9.2 (95%CI 6.9-11.5) months , which was significantly shorter than patients with dermatologic toxicities (17.5 months, 95%CI 8.0-27.0) (P < 0.001, Figure 6A). For patients with EC, median OS was 11.9 (95%CI 7.5-16.3) months in those without dermatologic toxicities and 23.3 (95%CI 15.9-30.7) months in patients with dermatologic toxicities (P = 0.003, Figure 6B). For patients with GC, the median OS was 8.5 (95%CI 6.6-10.4) and 14.3 (95%CI 10.4-18.1) months in those without or with dermatologic toxicities, respectively (P = 0.004, Figure 6C). In the logistic regression model, we found that ECOG PS at ICI initiation, PD-L1 expression, corticosteroids use, and CD4+/CD8+ ratio were potentially correlated with dermatologic toxicities (P <0.05, Table 5). Multivariate analysis further showed that PD-L1 expression (P < 0.001), corticosteroids use (P = 0.032), and CD4+/CD8+ ratio (P = 0.005) can predict dermatologic toxicities independently.
Table 5.Clinicopathological characteristics associated with the incidence of dermatologic toxicities
|
|
Univariate analysis
|
Multivariate analysis
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Characteristics
|
OR
|
95%CI
|
P-value
|
OR
|
95%CI
|
P-value
|
Age
|
|
|
|
|
|
|
<65
|
0.570
|
0.286-1.135
|
0.110
|
|
|
|
>65
|
Reference
|
|
|
|
|
|
Sex
|
|
|
|
|
|
|
Male
|
0.718
|
0.324-1.590
|
0.414
|
|
|
|
Female
|
Reference
|
|
|
|
|
|
ECOG PS at ICI initiation
|
|
|
|
|
|
|
0-1
|
0.445
|
0.223-0.891
|
0.022
|
0.655
|
0.253-1.697
|
0.384
|
2
|
Reference
|
|
|
|
|
|
HBP
|
|
|
|
|
|
|
Yes
|
1.549
|
0.684-3.508
|
0.294
|
|
|
|
No
|
Reference
|
|
|
|
|
|
DM
|
|
|
|
|
|
|
Yes
|
1.500
|
0.458-4.915
|
0.503
|
|
|
|
No
|
Reference
|
|
|
|
|
|
Tumor type
|
|
|
|
|
|
|
Esophageal cancer
|
0.853
|
0.432-1.687
|
0.648
|
|
|
|
Gastric cancer
|
Reference
|
|
|
|
|
|
Distant metastases
|
|
|
|
|
|
|
Yes
|
0.718
|
0.324-1.590
|
0.414
|
|
|
|
No
|
Reference
|
|
|
|
|
|
PD-L1 expression
|
|
|
|
|
|
|
>1%
|
7.091
|
2.964-16.962
|
<0.001
|
6.211
|
2.371-16.270
|
<0.001
|
<1%
|
Reference
|
|
|
|
|
|
Antibiotic use
|
|
|
|
|
|
|
Yes
|
0.728
|
0.284-1.869
|
0.509
|
|
|
|
No
|
Reference
|
|
|
|
|
|
Corticosteroids use
|
|
|
|
|
|
|
Yes
|
0.297
|
0.130-0.675
|
0.004
|
0.315
|
0.109-0.907
|
0.032
|
No
|
Reference
|
|
|
|
|
|
HGB (g/L)
|
1.004
|
0.988-1.021
|
0.620
|
|
|
|
NLR
|
1.000
|
0.923-1.084
|
0.995
|
|
|
|
LMR
|
1.031
|
0.822-1.293
|
0.792
|
|
|
|
LDH (IU/L)
|
0.999
|
0.998-1.001
|
0.233
|
|
|
|
CEA (ng/ml)
|
1.001
|
0.997-1.004
|
0.790
|
|
|
|
CA19-9 (U/mL)
|
1.000
|
0.998-1.002
|
0.835
|
|
|
|
CD4+/CD8+ ratio
|
0.257
|
0.129-0.515
|
<0.001
|
0.306
|
0.134-0.699
|
0.005
|