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

ABSTRACT 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.