Efficacy of immunotherapy in sarcomatoid lung cancer, a case report and literature review.

Sarcomatoid carcinoma is a subtype of non-small cell lung cancer (NSCLC) characterized by mesenchymal - epithelial transition component and awful prognosis. In this report, based on a case of stage IV lung sarcomatoid carcinoma with an extraordinary evolution and survival over 4 years, we address unresolved questions about the treatment of this cancer. We also make a literature review about the key factors that characterize this histology and that should be considered when treating those patients. Sarcomatoid carcinoma presents with mutations as KRAS, EGFR, ALK or MET in up to 70% of cases, and an important expression of PD-L1 (also called B7-H1), which can influence treatment of those patients with new drugs as immune checkpoint inhibitors. Immunotherapy has changed the horizon of patients with stage IV lung cancers without driver mutations, as their survival has improved extraordinary. Moreover, radical treatments are being considered in long survivors with oligometastatic disease. In this report, we review targeted and radical therapy, treatment duration and the mechanisms responsible of disease evolution of sarcomatoid tumors.