Metastatic gastric cancer has long been labeled as a drug-barren area on site. Various clinical studies have been conducted to develop new therapies for the area, but most have been unsuccessful. This is due to the tumor's heterogeneity, which makes it difficult to prove the efficacy of treatments.

However, the recent introduction of immuno-oncology drugs and targeted therapies has changed the treatment strategy in clinical practice.

# The treatment paradigm for gastric cancer has now reached a state where the use of anticancer drugs is indispensable.

However, due to obstacles in the domestic health insurance system, such as reimbursement and companion diagnostics, the use