Clinical and molecular characteristics of pulmonary sarcomatoid carcinoma

Background/Aims: Pulmonary sarcomatoid carcinoma (PSC) is a poorly differentiated non-small cell lung cancer (NSCLC) that contains components of spindle or giant cells. Owing to its low prevalence, there are insufficient data regarding its clinical features, therapeutic strategies and prognosis. Methods: The medical records of 26 patients diagnosed with PSC from January 2009 to June 2015 were reviewed and analyzed for clinicopathological characteristics, treatment modality, and outcomes. Results: The median age was 69.5 years. Twenty-three patients (88%) were male. Twenty-four patients (92%) were smokers. The median time from symptom onset to diagnosis was one month. Eighteen patients (69%) were diagnosed at an advanced stage. Pleomorphic carcinoma was the most common subtype, and epidermal growth factor receptor (EGFR) mutation was positive in two of 11 patients. Among 13 patients tested for programmed death ligand 1 (PD-L1) immunohis-tochemistry assay, eight showed high expression of PD-L1. The median overall survival (OS) of all patients was 9.5 months. In total, 12 patients were treated with chemotherapy: nine with platinum-based doublet therapy, two with tyrosine kinase inhibitor, and one with docetaxel. Seven patients showed partial response or stable disease. The median OS and progression-free survival of patients who received chemotherapy were 8.7 and 2.8 months, respectively. Conclusions: PSC was more common in males, smokers, and the elderly, with worse prognosis than ordinary NSCLC; chemotherapy response was favorable, and EGFR mutation status and PD-L1 expression may offer more therapeutic options.