Assessing grade 3 and grade 4 immunotherapy-induced dermatologic toxicities at a tertiary medical center.

Abstract

e24192 Background: Immune checkpoint inhibitors (ICIs) are increasingly used across multiple malignancies but are associated with immune-related adverse events, including dermatologic toxicities that may necessitate treatment interruption or discontinuation. Data describing the prevalence, severity, and risk factors for high-grade dermatologic toxicities in real-world settings remain limited. Methods: We conducted a single-center retrospective cohort study of adult patients treated with ICIs at a tertiary medical center and affiliated oncology clinic between January 2021 and December 2024. Patients receiving PD-1, PD-L1, and/or CTLA-4 inhibitors were included. Dermatologic immune-related adverse events were identified and graded using CTCAE criteria. Demographics, comorbidities, tumor type, and treatment characteristics were compared between patients with and without dermatologic toxicity. Multivariate logistic regression was used to identify predictors of moderate-to-severe toxicity (Grade ≥2). Results: Among 273 patients receiving ICIs, 44 (16.1%) developed dermatologic toxicity. Grade 1 events occurred in 19 patients (43.2%), Grade 2 in 15 (34.1%), Grade 3 in 4 (9.1%), and Grade 4 in 6 (13.6%), resulting in an overall Grade 3–4 toxicity rate of 3.7%. Patients with dermatologic toxicity had a higher mean BMI compared to those without toxicity (28.26 vs. 26.61 kg/m², p = 0.0169) and were older on average (68.6 vs. 63.3 years, p = 0.0599). Race and alcohol use differed significantly between groups, while sex was not associated with toxicity. PD-1 inhibitors were the most commonly used agents (93.4%), while CTLA-4 inhibitors were used in 10.3% of patients. In multivariate analysis, skin cancer diagnosis was the only independent predictor of Grade ≥2 dermatologic toxicity compared with lung cancer (adjusted OR 5.88; 95% CI 1.19–30.18; p = 0.0306). CTLA-4 inhibitor exposure and diabetes mellitus showed numerically higher odds but were not statistically significant. Conclusions: In this real-world cohort, dermatologic toxicities associated with ICIs were relatively common, though severe Grade 3–4 events were rare. Higher BMI and skin cancer diagnosis were associated with increased risk, with skin cancer emerging as the sole independent predictor of moderate-to-severe toxicity. These findings underscore the importance of risk stratification and early dermatologic evaluation to optimize immunotherapy management.