Role of Immunotherapy in Stage IV Large Cell Neuroendocrine Carcinoma of the Lung

BACKGROUND: Despite approvals of immune checkpoint inhibitors in both small cell and non-small cell lung cancers, the role of immunotherapy in large cell neuroendocrine carcinoma (LCNEC) in lung is undefined. METHODS: Using the National Cancer Database (NCDB), Stage IV lung LCNEC cases diagnosed from 2014 to 2016 were analyzed. Information regarding cancer treatment was limited to first course of therapy, including surgery for primary lesion, radiation, chemotherapy, and immunotherapy. Survival analysis was performed using Kaplan-Meier curves and Log-rank tests. Cox proportional hazard model was used for multivariate analysis. RESULTS: Among 661 eligible cases, 37 patients were treated with immunotherapy. No significant association between use of immunotherapy and clinical demographics was observed except for use of chemotherapy (p=0.0008). Chemotherapy was administered in 34 (92%) and 406 (65%) in immunotherapy and non-immunotherapy groups, respectively. Use of immunotherapy was associated with improved overall survival (Log-rank p=0.0018). Landmark analysis in the immunotherapy group showed 12 and 18-month survivals of 34.0% and 29.1%, respectively, whereas those in the non-immunotherapy group were 24.1% and 15.0%, respectively. Multivariate analysis demonstrated that female sex (HR=0.79, p=0.0063), liver metastases (HR=0.75, p=.0392), surgery (HR= 0.50, p<0.0001) use of chemotherapy (HR= 0.44, p<0.0001), and use of immunotherapy (HR=0.64, p=0.0164) had statistical significance. Propensity score matching in overall survival analysis showed a nonsignificant trend (p=0.0733) in favor of immunotherapy treatment. CONCLUSION: This retrospective study using NCDB suggests that use of immunotherapy may improve survival of LCNEC patients.