An observational study on the efficacy of targeted therapy for pulmonary sarcomatoid carcinoma

Background: Pulmonary sarcomatoid carcinoma is a rare tumor that is resistant to cytotoxic agents. This observational study aimed to evaluate the detection rate of driver gene alteration and the efficacy of targeted therapy for pulmonary sarcomatoid carcinoma. Methods: We established a database of patients with pulmonary sarcomatoid carcinoma and their clinical information, including EGFR mutation, ALK fusion gene, ROS1 fusion gene, BRAF mutation, and MET exon 14 skipping mutation. The present study retrieved and analyzed the data of patients with pulmonary sarcomatoid carcinoma in whom driver gene alterations were evaluated, and the survival duration after the initiation of treatment with targeted therapy was examined. Results: A total of 44 patients were included in the present study. The EGFR mutation, ALK fusion gene, and MET exon 14 skipping mutation were detected in 2/43 patients (4.7%), 2/34 patients (5.9%), and 2/16 patients (12.5%), respectively. The ROS1 fusion gene (0/18 patients) and BRAF mutation (0/15 patients) were not detected. Female patients (P = 0.063, Fisher’s exact test) and patients without smoking history (P = 0.025, Fisher’s exact test) were the dominant groups in which any driver mutation was detected. Five patients with driver gene alterations were treated with targeted therapy. Progression-free survival (PFS) was 1.3 months and 1.6 months in 2 of the patients treated with gefitinib. Two patients with the ALK fusion gene showed 2.1 and 14.0 months of PFS from the initiation of treatment with crizotinib, and a patient with the MET exon 14 skipping mutation showed 9.7 months of PFS from the initiation of treatment with tepotinib. Conclusion: The EGFR mutation, ALK fusion gene, and MET exon 14 skipping mutation were detected in patients with pulmonary sarcomatoid carcinoma in clinical practice, and some patients achieved long survival times after receiving targeted therapy. Further investigation is necessary to evaluate the efficacy of targeted therapy for pulmonary sarcomatoid carcinoma.