The median age of the 237 enrolled patients was 59 years (range, 34–86) and comprised of 109 males and 128 females. The median OS and PFS were 11.41 m and 5.42m, respectively. 52.74%patients received first-line immunotherapy. Other patients were treated with first- or second-line chemotherapy alone. 181 patients had received immunotherapy combined with chemotherapy, whereas 56 patients received either immunotherapy monotherapy or combined with anti-angiogenic agents. All patients were of the microsatellite stable (MSS) gastric cancer subtype. 112 patients treated with nivolumab and 57 patients with pembrolizumab, 46 patients with Sintilimab, or 22 patients with toripalimab. The median PLR was 199.2(range, 29.9–1375.6). The areas under curve for PLR at 6- and 12-months were 0.60 and 0.65, respectively based on the most prominent point with a sensitivity of 69.7% and specificity of 66.1% (Fig. 1). Based on these values, the optimal cutoff point for PLR at 6-months and 12 months was 139.41 (p < 0.001). Furthermore, it demonstrated significantly different PFS and OS when patients stratified based on PLR quartile values was (p < 0.05) (Fig. 2).
For the ROC analyses, patients were cohorted into PLR < 139.41 group (low PLR) and PLR ≥ 139.41 group (elevated PLR). There was no significant variability in ECOG-PS, gender, age, number of metastatic sites, PD-L1 expression status, smoking and drinking history, primary tumor site, histological differentiation, surgery history, presence of liver metastasis, carbohydrate antigen 19 − 9 (CA19-9), carcinoembryonic antigen (CEA), and anti-PD-1 type and treatment line or type, risk of malnutrition (Table 1).Of the 237 patients, 30.85% patients in the PLR < 139.41 group demonstrated an objective response (1 CR and 28 PR). This in contrast to only 32.17% in the PLR ≥ 139.41 group. 86.17% of patients in the low PLR group demonstrated confirmed disease control rate (DCR), while only 82.52% achieved this status in the elevated PLR group. The two groups demonstrated no differences in terms of ORR and DCR (p = 0.887, p = 0.476) (Table 2).
Table 1
The characteristics of the analyzed patients in different groups
Characteristics | PLR < 139.41 | PLR > = 139.41 | p value |
N | % | N | % | |
No. patients | 94 | | 143 | | |
Gender n (%) | | | | | 0.184 |
Male | 38 | 40.43% | 71 | 49.65% | |
Female | 56 | 59.57% | 72 | 50.35% | |
Age median = 59 n (%) | | | | | 0.409 |
<59 | 31 | 32.98% | 56 | 39.16% | |
>=59 | 63 | 67.02% | 87 | 60.84% | |
PD-L1 n (%) | | | | | 0.396 |
Positive (CPS > 1%) | 44 | 46.81% | 63 | 44.06% | |
Negative (CPS < 1%) | 29 | 30.85% | 37 | 25.87% | |
Unknown | 21 | 22.34% | 43 | 30.07% | |
ECOG PS n (%) | | | | | 0.415 |
0 | 30 | 31.91% | 35 | 24.48% | |
1 | 47 | 50.00% | 76 | 53.15% | |
>=2 | 17 | 18.09% | 32 | 22.38% | |
Tumor_location n (%) | | | | | 0.509 |
Cardia | 27 | 28.72% | 32 | 22.38% | |
Body/Fundus | 56 | 59.57% | 95 | 66.43% | |
Pylorus | 11 | 11.70% | 16 | 11.19% | |
Histological_differentiation n (%) | | | | | 0.591 |
Poorly | 47 | 50.00% | 81 | 56.64% | |
Moderately | 43 | 45.74% | 56 | 39.16% | |
Well | 4 | 4.26% | 6 | 4.20% | |
Surgery history | | | | | 0.186 |
Yes | 49 | 52.2% | 62 | 43.3% | |
NO | 45 | 47.8% | 81 | 56.7% | |
No. of metastasis organs n (%) | | | | | 0.598 |
<2 | 52 | 55.32% | 74 | 51.75% | |
>=2 | 42 | 44.68% | 69 | 48.25% | |
Liver metastasis n (%) | | | | | 0.344 |
Yes | 40 | 42.55% | 52 | 36.36% | |
No | 54 | 57.45% | 91 | 63.64% | |
Smoking history | | | | | 0.566 |
Yes | 41 | 43.62% | 57 | 39.86% | |
No | 53 | 56.38% | 86 | 60.14% | |
Drinking history | | | | | 0.602 |
Yes | 52 | 55.32% | 84 | 58.74% | |
No | 42 | 44.68% | 59 | 41.26% | |
Risk of malnutrition | | | | | 0.151 |
1–2 | 67 | 71.3% | 89 | 62.2% | |
3–4 | 27 | 28.7% | 54 | 37.8% | |
CEA n (%) | | | | | 0.507 |
<5 ng/ml | 45 | 47.87% | 76 | 53.15% | |
>=5 ng/ml | 49 | 52.13% | 67 | 46.85% | |
CA199 n (%) | | | | | 0.424 |
<37 U/mL | 50 | 53.19% | 84 | 58.74% | |
>=37 U/mL | 44 | 46.81% | 59 | 41.26% | |
PD-1 inhibitor | | | | | 0.939 |
Nivolumab | 46 | 48.93% | 66 | 46.15% | |
Pembrolizumab | 20 | 21.27% | 37 | 25.87% | |
Sintilimab | 18 | 19.14% | 28 | 19.58% | |
Toripalimab | 10 | 10.64% | 12 | 8.39% | |
Anti-pd-1 treatment line n (%) | | | | | 0.676 |
First line | 52 | 55.32% | 73 | 51.05% | |
Second line | 35 | 37.23% | 55 | 38.46% | |
Third line | 7 | 7.45% | 15 | 10.49% | |
Anti-pd-1 treatment type n (%) | | | | | 0.717 |
Anti-pd-1 monotherapy | 5 | 5.32% | 11 | 7.69% | |
Combination therapy | | | | | |
anti-pd-1 plus chemotherapy | 74 | 78.72% | 107 | 74.83% | |
anti-pd-1 plus anti-angiogenic therapy | 15 | 15.96% | 25 | 17.48% | |
Table 2
Treatment response in the PLR < 139.41 group and in the PLR > = 139.41 group
Response | PLR < 139.41 | PLR > = 139.41 | |
N | % | N | % | P value |
No. patients | 94 | | 143 | | |
Response | | | | | |
CR | 1 | 1.06% | 2 | 1.40% | |
PR | 28 | 29.79% | 44 | 30.77% | |
SD | 52 | 55.32% | 72 | 50.35% | |
PD | 13 | 13.83% | 25 | 17.48% | |
ORR | | | | | 0.887 |
CR + PR | | 30.85% | | 32.17% | |
DCR | | | | | 0.476 |
CR + PR + SD | | 86.17% | | 82.52% | |
Univariate analyses allowed for identification of clinical factors which correlated to PFS or OS. Patients with raised PLR had a median PFS of 4.75m in contrast to the 7.93m seen in those with low PLR (HR = 0.57`, 95% CI, 0.43–0.76, p = 0.002) (Fig. 3). Those with low PLR had a longer median OS than those with elevated PLR (13.46m vs 10.71m, HR = 0.57`, 95% CI, 0.42–0.78, p = 0.004) (Fig. 3). Univariate analysis revealed that those patients with low PLR group or receiving anti-pd-1 plus chemotherapy had better OS than patients with elevated PLR or receiving immunotherapy monotherapy or combined with antigenic agents (P < 0.05) (Tables 4).However, multivariate analysis found only PLR to be an independent prognostic biomarker for PFS (HR = 0.58, 95%CI,0.43–0.78, P < 0.001) (Tables 3). PLR and antipd-1 treatment type ,surgery history were three independent prognostic factors for OS upon multivariate analysis (HR = 0.59, 95% CI, 0.43–0.82, P = 0.001, HR = 1.92, 95% CI, 1.29–2.85, P = 0.001; HR = 1.53, 95% CI, 1.11–2.11, P = 0.009, respectively) (Table 4). We therefore conclude that elevated PLR was associated with inferior PFS and OS.
Table 3
Univariate analysis and multivariate analysis of progression free time (PFS)
Variable Category | Category | Univariate analysis | Multivariate analysis |
| | p-value | HR (95% CI) | p-value |
Gender | Female versus Male | 0.628 | 1.00(0.74–1.34) | 0.997 |
Age | >=59 versus < 59 | 0.466 | 0.86(0.633–1.17) | 0.354 |
ECOG PS | >=2 versus 0–1 | 0.063 | 1.29(0.92–1.82) | 0.136 |
Tumor location | Pylorus versus Body/Fundus versus Cardia | 0.328 | 1.04(0.81–1.34) | 0.716 |
Histological differentiation | Poorly versus Moderately and Well | 0.681 | 1.06(0.79–1.41) | 0.676 |
Surgery | No verse Yes | 0.095 | 1.21(0.90–1.63) | 0.196 |
No.of metastasis organs | >=2 verse =1 | 0.877 | 0.93(0.69–1.25) | 0.650 |
Liver metastasis | No verse Yes | 0.740 | 0.94(0.69–1.27) | 0.714 |
Smoking history | No verse Yes | 0.321 | 1.07(0.79–1.44) | 0.660 |
Drinking history | No verse Yes | 0.155 | 0.78(0.58–1.05) | 0.105 |
PD-1 Inhibitor | Nivolumab verse Pembrolizumab verse Sintilimab verse Toripalimab | 0.742 | 1.02(0.89–1.18) | 0.702 |
Anti-pd-1 treatment line | Second or more line verse First line | 0.354 | 1.01(0.73–1.39) | 0.947 |
Anti-pd-1 treatment type | anti-pd-1 monotherapy or antiagenis verse anti-pd-1 plus chemotherapy | 0.137 | 1.278(0.88–1.85) | 0.195 |
PLR | <139.41 versus > = 139.41 | 0.002 | 0.58(0.43–0.78) | 0.000 |
CI, confidence interval; ECOG PS, Eastern Cooperative Oncology Group Performance Status; PLR, platelet to lymphocyte ratio HR, hazard ratio. |
Table 4
Univariate analysis and multivariate analysis of overall survival time (OS)
Variable Category | Category | Univariate analysis | Multivariate analysis |
| | p-value | HR (95% CI) | p-value |
Gender | Female versus Male | 0.448 | 1.19(0.87–1.63) | 0.261 |
Age | >=59 versus < 59 | 0.878 | 1.00(0.72–1.40) | 0.968 |
ECOG PS | >=2 versus 0–1 | 0.694 | 0.82(0.56–1.18) | 0.291 |
Tumor location | Pylorus versus Body/Fundus versus Cardia | 0.406 | 1.08(0.82–1.41) | 0.568 |
Histological differentiation | Poorly versus Moderately and Well | 0.984 | 0.94(0.69–1.27) | 0.701 |
Surgery | No verse Yes | 0.014 | 1.53(1.11–2.11) | 0.009 |
No.of metastasis organs | >=2 verse =1 | 0.561 | 0.95(0.69–1.30) | 0.765 |
Liver metastasis | No verse Yes | 0.236 | 1.18(0.85–1.65) | 0.300 |
Smoking history | No verse Yes | 0.154 | 1.26(0.91–1.75) | 0.153 |
Drinking history | No verse Yes | 0.926 | 1.07(0.78–1.47) | 0.671 |
PD-1 Inhibitor | Nivolumab verse Pembrolizumab verse Sintilimab verse Toripalimab | 0.734 | 0.98(0.84–1.15) | 0.845 |
Anti-pd-1 treatment line | Second or more line verse First line | 0.288 | 0.92(0.65–1.31) | 0.665 |
Anti-pd-1 treatment type | anti-pd-1 monotherapy or antiagenis verse anti-pd-1 plus chemotherapy | 0.001 | 1.92(1.29–2.85) | 0.001 |
PLR | <139.41 versus > = 139.41 | 0.004 | 0.59(0.43–0.82) | 0.001 |
CI, confidence interval; ECOG PS, Eastern Cooperative Oncology Group Performance Status; PLR, platelet to lymphocyte ratio HR, hazard ratio. |