Prognostic Significance of Pretreatment Blood‐Based Biomarkers in Penile Cancer: A Multicenter Retrospective Study in Japan

OBJECTIVES: Penile cancer is a rare malignancy, and multicenter data evaluating prognostic biomarkers in the Japanese population are limited. This study aimed to assess the prognostic significance of pretreatment blood-based biomarkers in patients with penile cancer. METHODS: We conducted a multicenter retrospective cohort study including 111 patients with penile cancer treated between January 2005 and December 2023 at ten institutions participating in the West Japan Uro-oncology Collaboration Group. Cancer-specific survival (CSS) was analyzed using the Kaplan-Meier method and Cox proportional hazards model. Receiver operating characteristic analyses were performed to determine optimal cutoff values for the neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), and squamous cell carcinoma antigen (SCC-Ag). A composite biomarker score was calculated based on the number of elevated biomarkers. RESULTS: The 5-year overall survival and CSS rates were 71.1% and 77.4%, respectively. In univariate analyses, elevated PLR, elevated SCC-Ag, and higher composite biomarker scores were significantly associated with poorer CSS. In multivariate analysis, advanced clinical nodal status (≥ cN2) and distant metastasis (cM1) remained independent predictors of CSS, whereas blood-based biomarkers did not retain independent prognostic significance after adjustment for established clinicopathological factors. Kaplan-Meier analyses demonstrated significantly worse CSS in patients with high PLR, high SCC-Ag levels, and higher composite biomarker scores. CONCLUSIONS: Pretreatment blood-based biomarkers, particularly PLR and SCC-Ag, are associated with prognosis in penile cancer. Although they did not retain independent prognostic factors after adjustment, these biomarkers may provide complementary prognostic information and help identify high-risk patients in clinical practice.