HEMATOLOGIC BIOMARKERS AS PREDICTORS OF IMMUNE-RELATED CUTANEOUS ADVERSE EVENTS IN PATIENTS TREATED WITH IMMUNE CHECKPOINT INHIBITORS

Abstract

Purpose: The study aimed to evaluate the association between baseline hematologic parameters and the development of immune-related cutaneous adverse events (irCAEs) in patients treated with immune checkpoint inhibitors (ICIs). Identifying predictive biomarkers for cutaneous toxicity is essential for early risk stratification and improved patient management. Material/Methods: This retrospective observational study included adult patients with solid malignancies who received ICIs (anti–PD-1, anti–PD-L1, or anti–CTLA-4) and developed irCAEs. Data were collected from two oncology centers between 2018 and 2024, including complete blood counts and inflammatory markers: absolute lymphocyte count (ALC), eosinophil count (AEC), neutrophil-to-lymphocyte ratio (NLR), and platelet-to-lymphocyte ratio (PLR). Immune-related cutaneous adverse events were classified by their clinical morphology, and their severity was graded using the Common Terminology Criteria for Adverse Events (CTCAE). Results: Higher AEC and ALC, along with lower NLR, were significantly associated with the incidence and severity of cutaneous irCAEs. AEC emerged as the strongest predictor (ρ = +0.61, β = +0.52), followed by ALC (ρ = +0.38, β = +0.29) and NLR (ρ = −0.58, β = −0.41). Regression analysis explained 47% of the variance in cutaneous toxicity, and receiver operating characteristic (ROC) analysis showed AEC (AUC = 0.83) and NLR (AUC = 0.76) had strong predictive value. Conclusions: Baseline AEC, ALC, and NLR are reliable predictors for the development of immune-related cutaneous adverse events in ICI-treated patients. These hematologic markers can serve as accessible, practical tools for early toxicity prediction, allowing for personalized monitoring strategies and timely interventions.