Abstract: 【Abstract】 Objective To evaluate the clinical efficacy and safety of sonidegib in the treatment of locally advanced basal cell carcinoma （laBCC）. Methods This case series study retrospectively analyzed the clinical data from 8 patients with laBCC treated with sonidegib （200 mg/d） at the Affiliated Hospital of Yunnan University from March 2024 to January 2025. Therapeutic efficacy, tumor response rates, and adverse events were evaluated. Results Among the 8 patients with laBCC, 3 were males and 5 were females, with a median age of 74 years and disease durations of 9.13 ± 6.02 years. Tumor shrinkage was observed in all 8 patients after treatment, with shrinkage rates ranging from 2.33% to 100.00%. Five patients achieved a tumor shrinkage rate of ≥ 30%, including 2 with complete clinical regression of tumors （1 achieved a pathologically confirmed complete response）. In the remaining 3 patients with suboptimal tumor shrinkage, reduction in tumor volume and thickness allowed for subsequent surgical intervention. All the 8 patients experienced adverse events, with creatine kinase elevation being the most common （6/6, up to grade 3）, followed by alopecia （3/8）, hypogeusia （2/8）, and muscle spasms （1/8）. Most adverse events were manageable through dose adjustment or temporary treatment suspension. Conclusion Sonidegib is effective for the treatment of laBCC, but close monitoring of adverse events, particularly creatine kinase elevation, is necessary.

Key words: Carcinoma, basal cell, Neoplasm recurrence, local, Sonidegib, Treatment outcome, Drug-related side effects and adverse reactions