Cutaneous Immune-Related Adverse Events due to Immune Checkpoint Inhibitors: A Clinical Phenotype-Cancer Subtype Association

Background and Aim Immune checkpoint inhibitors (ICIs) block the interaction of checkpoint proteins, increasing the anti-tumor response from T lymphocytes. However, because this response is nonspecific, it can cause skin damage, resulting in cutaneous immune-related adverse events (cirAEs). In this study, we aimed to investigate the association between the cirAEs phenotype and cancer subtype at our oncology center. Materials and Methods This is a retrospective single-center study conducted at the Princess Noorah Oncology Center in Jeddah, Saudi Arabia. It included all adult patients receiving ICI as cancer therapy from January 2016 through September 2023. Data were analyzed to evaluate the prevalence and phenotypes of cutaneous immune-related adverse events (cirAEs), treatment outcomes, and cancer subtypes. Chi-square and Mann–Whitney U tests were used to assess associations between cirAE status and categorical or continuous variables (age, BMI), respectively. Statistical significance was set at p < 0.05. Analyses were performed using JMP software, version 10.0 (SAS Institute Inc., Cary, NC, USA). Results Out of 201 patients, 116 were male (57.7%), 85 were female (42.3%). The prevalence of cirAEs was 36–17.9%; the most common culprit drug was pembrolizumab. Most genitourinary malignancies (N = 10, 27.78%). The most common cirAE clinical phenotype was ulceration (36%), and the median cirAEs from initiation of ICI were 53.5 days. Conclusion ICIs have been associated with the development of cirAE in 17.9% of our cancer patients, with ulceration being the most common phenotype and pembrolizumab being the most common culprit medication. The cirAE was mostly prevalent among patients with genitourinary cancers. Further prospective studies are needed.