[Nivolumab Therapy for Synchronous Double Primary Lung and Gastric Cancers]

A 70-year-old man who was diagnosed with a cStage ⅣA lung adenocarcinoma was in a stable condition for a long time after the first chemotherapy with gefitinib. However, 2 years 4 months later, the lung cancer progressed, and he was diagnosed with Stage Ⅲ gastric cancer. Since the administration of afatinib as the second-line chemotherapy was ineffective, nivolumab was administered as the third-line chemotherapy. The lung cancer showed a partial response to nivolumab treatment, but the gastric cancer remained unresponsive. We report a rare case of immune checkpoint inhibitor administration for synchronous double primary cancers.