Systemic Inflammation Indexes and Risk of Immune-related Adverse Events in Patients With Metastatic Urothelial Carcinoma Treated With Immunotherapy.

Background/aim: Immune checkpoint inhibitors (ICIs) have revolutionized the treatment of metastatic urothelial carcinoma (mUC). However, they could be associated with immune-related adverse events (irAEs), which may be clinically significant. Identifying clinical characteristics that may be associated with a higher risk of irAEs is of great importance.

Patients and methods: We retrospectively collected data from all patients who received anti-PD1 or anti-PD-L1 for metastatic UC at our Institution from January 2017 to December 2022. Patients were dichotomized according to baseline neutrophil-to-lymphocyte ratio (NLR), systemic immune-inflammation index (SII), and platelet-to-lymphocyte ratio (PLR) values. We performed univariate and multivariate logistic regression to determine the association between baseline characteristics and the development of irAEs.

Results: A total of 119 patients were identified. At a median follow-up of 29.6 months, 96 patients progressed and 82 died. Forty-five patients developed irAEs of any grade, 8 patients developed grade 3 toxicities. In the univariate analysis PS of 0 (p<0.01), baseline NLR <3.52, baseline PLR <194 (p=0.04) and baseline SII <906 (p=0.01) were significantly associated with a higher risk of developing irAEs, whereas in the multivariate analysis only PS=0 (p<0.01) and NLR <3.52 (p=0.03) maintained their correlation. Median progression-free survival (mPFS) and overall survival (mOS) were significantly longer in patients with NLR <3 (mPFS 3.8 vs. 2.6 months, p=0.01; mOS 15.3 vs. 5.6 months, p=0.002) and PS=0 (mPFS 4.8 vs. 2.1 months, p<0.001; mOS 15.3 vs. 3.8 months, p<0.001).

Conclusion: Low baseline NLR, PLR, and SII and good PS are associated with a higher risk of developing irAEs in patients treated with ICIs for mUC.