Platelet-to-lymphocyte ratio as a prognostic biomarker in relapsed or refractory classic Hodgkin lymphoma treated with PD-1-based salvage therapy

PD-1 inhibitors have reshaped the treatment landscape of relapsed or refractory classic Hodgkin lymphoma (r/r cHL), yet validated biomarkers in this setting remain limited. We evaluated the prognostic relevance of the neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) in patients receiving PD-1-based salvage therapy. Patients with r/r cHL who received PD-1-based salvage chemotherapy at two hospitals between 2018 and 2023 were retrospectively identified. Optimal NLR and PLR cutoffs were determined using ROC analysis. Progression-free survival (PFS) and overall survival (OS) were estimated using the Kaplan–Meier method, and prognostic factors were evaluated using Cox regression. The findings were further validated in an independent cohort from 2 additional centers. Patients from both cohorts who underwent autologous stem cell transplantation (ASCT) were pooled for an exploratory transplantation subgroup analysis. A total of 127 patients were included, comprising 48 relapsed (37.8%) and 79 refractory (62.2%) cases. ROC analysis identified optimal cutoffs of 3.0 for NLR and 282.0 for PLR. In survival analysis, elevated NLR and PLR were both associated with inferior 3-year PFS and OS. In multivariable analysis, PLR ≥ 282.0 remained significantly associated with shorter PFS (HR 2.027, 95% CI 1.213–3.389; P = 0.007) and OS (HR 3.874, 95% CI 1.434–10.464; P = 0.008), whereas NLR did not retain prognostic significance. In the independent validation cohort of 64 patients, PLR ≥ 282.0 was still significantly associated with lower 3-year PFS and OS. Among 60 patients in the pooled ASCT subgroup, PLR ≥ 282.0 was associated with inferior 3-year PFS (46.2% vs 82.1%; P = 0.012) and OS (75.0% vs 97.8%; P = 0.004). PLR represents a promising prognostic biomarker in patients with r/r cHL receiving PD-1-based salvage therapy. Prospective validation is required to confirm its prognostic value and clarify its potential contribution to risk stratification in this treatment setting.