Clinical analysis of 21 cases with non-small cell lung cancer transforming to small cell lung cancer

XU Lingling; YANG Jingwen; YE Wei; WU Pengfei; CHEN Maoxi; YAO Yuanyuan; XU Ning

doi:10.3969/j.issn.1009-0460.2025.04.005

Abstract：Objective To analyze the clinical characteristics and prognostic factors of the transformation from non-small cell lung cancer(NSCLC)to small cell lung cancer(SCLC),and to provide references for clinical diagnosis and treatment practices.Methods A retrospective analysis was conducted on the baseline characteristics and clinical features of 21 patients with NSCLC-to-SCLC transformation.Prognostic factors were assessed using Cox proportional hazards regression model,and survival outcomes were analyzed by the Kaplan-Meier method.Results The systematic analysis of 21 patients with NSCLC-to-SCLC transformation demonstrated a median transformation time of 24 months,with significantly shorter duration in tyrosine kinase inhibitor(TKI)monotherapy versus combination therapy groups(13 vs.34 months,P<0.05).Transformation occurred across treatment lines(23.8%at 1st-line,33.3%at 2nd-line therapy).Univariate analysis confirmed epidermal growth factor receptor mutation status(P=0.039)and treatment modality(P=0.008)were factor influencing transformation time.Notably,85.7%(6/7)of tested patients retained original driver mutations,with some cases showing adenocarcinoma feature recurrence post-SCLC treatment.Additionally,38.1%patients continued targeted maintenance therapy,demonstrating a non-significant trend toward longer median overall survival compared to chemotherapy-based regimens(10 vs.7 months,P=0.106).Conclusion The treatment modality for NSCLC is an independent risk factor affecting the time to transformation to SCLC and subsequently impacts the overall survival.Reassessment of genetic mutations after transformation is highly instructive.Continuing TKI therapy in addition to chemotherapy after transformation may provide a certain degree of clinical benefit.