RESUMEN
Lung cancer is a major health concern worldwide, but new immunotherapeutic treatments for lung cancer have shown great promise and the prognosis for many severe cancers including lung cancer has been improving. In May 2017, the Food and Drug Administration approved pembrolizumab, a therapeutic antibody that blocks lymphocytic programmed death-1 (PD-1), as a first-line treatment for any solid tumor with specific genetic features. Pembrolizumab is a therapeutic antibody that blocks lymphocytic PD-1, the ligand of which (PD-L1) is expressed on tumor cells and which can prevent the immune system from recognizing and destroying tumors. Here, we report two cases of double cancer (case 1: lung and bladder cancer; case 2: gastric and lung cancer) in which pembrolizumab was effective for the treatment of both cancers in each patient.