Prognostic risk score and index including the platelet-to-lymphocyte ratio and lactate dehydrogenase in patients with metastatic or unresectable urothelial carcinoma treated with immune checkpoint inhibitors

Background Avelumab and pembrolizumab are administered after platinum-based chemotherapy for the treatment of metastatic urothelial carcinoma. We explored the prognostic factors and risk scores for predicting the outcomes of metastatic or unresectable urothelial carcinoma at the start of treatment with immune checkpoint inhibitors.Methods This retrospective study included patients with metastatic or unresectable urothelial carcinoma treated with avelumab or pembrolizumab after platinum-based chemotherapy between January 2017 and December 2022. Prognostic factors, including patient and tumor characteristics and blood data at the initiation of immune checkpoint inhibitor therapy, were examined.Results This study included 36 and 207 patients treated with avelumab and pembrolizumab, respectively, for metastatic or unresectable urothelial carcinoma. Eastern Cooperative Oncology Group performance status, presence of visceral metastases, platelet-to-lymphocyte ratio and lactate dehydrogenase levels were independent prognostic factors for predicting overall survival. The median overall survival of patients in the risk-score model was 58.5 months (score zero), 27.9 months (one), 13.1 months (two) and 3.9 months (three or higher). The C-index for overall survival was 0.718 for the newly developed risk score compared with 0.679 for the Bellmunt score and 0.703 for the Bellmunt-C-reactive protein score. Additionally, the C-index for overall survival using the immune prognostic index derived from lactate dehydrogenase and the platelet-to-lymphocyte ratio was 0.646 compared with 0.615 for the Lung Immune Prognostic Index.Conclusions A risk score that includes the platelet-to-lymphocyte ratio and lactate dehydrogenase may serve as a useful model for predicting prognosis following the initiation of immune checkpoint inhibitors in patients with metastatic or unresectable urothelial carcinoma. This study identified PLR and LDH levels as significant prognostic factors for overall survival in metastatic urothelial carcinoma patients treated with avelumab or pembrolizumab, providing a new risk score model.