Response of advanced stage recurrent lymphoepithelioma-like carcinoma to nivolumab.

Lymphoepithelioma-like carcinoma (LELC) of lung is a rare tumor that is mostly reported in south-east Asian countries. The surgical removal is curative in the early stages but there is no consensus on the choice of chemotherapy for the treatment of advanced stage tumors. Most of the data on chemotherapy are based on small case series and retrospective studies. As per available data, this tumor responds to chemotherapy initially but recurrences are common. The use of conventional chemotherapy in recurrent tumors leads to cumulative toxicities in the long term. Due to lack of actionable mutations, targeted therapies are also not very useful. Immune check point inhibitors immune checkpoint inhibitors have shown survival benefit in patients with advanced stage non-small-cell and small cell carcinoma with better side effect profile than conventional chemotherapy. The role of immune checkpoint inhibitors in LELC is unknown. Though several studies have reported high expression of programmed cell death-1 (PD-1)/or its -ligand (PD-L1) in LELC providing a rationale for trial of these agents, the actual benefit of these agents in LELC has not been reported so far. In this case series, we report two cases of advanced stage LELC that progressed despite multiple lines of chemotherapy but responded favorably to a PD-1 inhibitor, nivolumab.