Comparative Analysis of Prognostic Potential of Pretreatment Blood-Based Biomarkers in Metastatic Bladder Cancer: Modified Glasgow Prognostic Score

<b>Background</b>: Metastatic bladder cancer (mBC) presents a significant global health challenge with a poor prognosis and considerably limited survival. Despite advancements in therapies, long-term survival remains difficult to predict. This study aimed to evaluate the prognostic potential of various pretreatment blood-based biomarkers, including the NLR, dNLR, LMR, PLR, SII, mGPS, CAR, AGR, PNI, PIV, and Bellmunt score, in mBC patients. <b>Methods</b>: A retrospective cohort of 133 patients from Hacettepe University Cancer Institute was analyzed. Kaplan-Meier survival analysis and Cox regression models were used to assess overall survival (OS) and progression-free survival (PFS). <b>Results</b>: There was a significant association between multiple biomarkers and OS in the univariate analysis, with a higher NLR, PLR, and SII linked to worse outcomes. However, in the multivariate analysis, only the modified Glasgow Prognostic Score (mGPS) maintained independent prognostic significance for OS (HR: 1.984, <i>p</i> = 0.013). This suggests that the mGPS, which reflects systemic inflammation and nutritional status, is a robust predictor of survival in mBC. <b>Conclusions</b>: This study highlights the potential of integrating blood-based biomarkers into clinical decision-making to improve personalized treatment strategies. However, prospective studies are needed to validate these findings and assess their applicability to newer therapies such as immune checkpoint inhibitors and antibody-drug conjugates.