Pretreatment platelet-to-lymphocyte ratio (PLR) as a prognosticating indicator for gastric cancer patients receiving immunotherapy

Background: Previous investigations suggest that systemic inflammation markers are able to provide prognostic value in several cancers. This study seeks to characterize the ability of pretreatment platelet-to-lymphocyte ratio (PLR) to prognosticate advanced or metastatic gastric cancer patients (AGC or MGC, respectively) receiving immunotherapy. Method: AGC and MGC patients exposed to PD-1 inhibitors from January 2016 - August 2021 in the Chinese PLA General Hospital were recruited. Correlations between PLR and overall survival (OS), progression-free survival (PFS), and immunotherapy-associated tumor response rates were determined. Results: : 237 patients were enrolled for this retrospective investigation. The 6month and 12 month PFS based on the area under the curve value was 0.60 and 0.65 (p<0.05). based on a calculated PLR cut-off value of 139.41, The PLR <139.41 group has a longer OS in contrast with the PLR ≥139.41 group (13.46m vs 10.71m, HR = 0.57`, 95% CI, 0.42-0.78, p =0.004). The PLR <139.41 group had a PFS of 7.93m in contrast to the 4.75m seen in those with PLR ≥139.41 group (HR = 0.57`, 95% CI, 0.43-0.76, p=0.002). The disease control rate (DCR) and objective response rate (ORR) were 86.17% and 30.85%, respectively, in the PLR <139.41 group, but were 82.52% and 32.17%, respectively in the PLR ≥139.41 group. Both groups did not show any marked differences in terms of ORR and DCR (p=0.887, p=0.476). PLR is an independent prognostic indicator for OS and PFS upon uni- and multivariate analyses (p<0.05). Conclusions: Pre-treatment PLR correlated significantly with PFS and OS in AGC and MGC patients who received immunotherapy. An elevated PLR may provide guidance on subsequent treatment options.