Ribociclib is an approved cyclin-dependent kinase 4/6 inhibitor for the treatment of hormone receptor–positive (HR+), human epidermal growth factor receptor 2–negative (HER2−) advanced breast cancer (ABC) when combined with endocrine therapy. Although pivotal clinical trials have clearly described hematologic, hepatic, and cardiac toxicities, data regarding ribociclib-associated cutaneous adverse events (CAEs) are still scarce. This retrospective cohort study included all patients with HR+/HER2− ABC who were treated with ribociclib at the Humanitas Cancer Center from June 2017 through December 2022. Clinical and pathological variables were collected together with the frequency, type, and management of CAEs attributed to ribociclib. Adverse events were graded according to the National Cancer Institute Common Terminology Criteria for Adverse Events (NCI-CTCAE), version 5.0. Progression-free survival (PFS) was assessed using the Kaplan–Meier method, and comparisons between groups were conducted with the log-rank test. Out of 91 treated patients, 13 (14.3%) developed ribociclib-related CAEs, with a mean time to onset of 3.9 months. Eczematous dermatitis represented the most common manifestation (53.8%), followed by maculopapular eruptions (15.4%). Pruritus was present in all 13 affected patients. Severity was classified as grade 3 in 8 cases, grade 2 in 4 cases, and grade 1 in 1 case. A multidisciplinary strategy combining ribociclib dose modification with dermatologic therapies (oral antihistamines, emollient creams, topical and/or systemic corticosteroids) enabled treatment continuation in the majority of patients. After a median follow-up of 20 months, median PFS was 13 months (range, 1–66), and patients who experienced CAEs showed significantly improved PFS curves (P = .04).This analysis characterizes the incidence and clinical spectrum of ribociclib-induced CAEs. Integrating structured dermatologic management into routine oncologic practice may help limit treatment discontinuation and could contribute to improved long-term clinical outcomes.
