Abstract
The patient was an 80-year-old man who was diagnosed with cStage IIIB non-small cell lung cancer (NSCLC) and early gastric cancer. The advanced lung cancer was treated with chemotherapy while the gastric cancer was monitored. Immune checkpoint inhibitors were effective against the lung cancer for a long period, but new gastric cancer appeared and progressed to an advanced stage, necessitating total gastrectomy 5 years after the diagnosis of NSCLC. The patient is currently being treated with a molecular targeted agent for progression of the lung cancer after gastrectomy. In the future, the number of cases with multiple primary cancers will increase alongside aging of the population and advances in cancer treatment, and a system for tumor-agnostic treatment selection and medical treatment will be necessary.
