Overview of Chemotherapy for Gastric Cancer

Gastric cancer (GC) is one of the most clinically challenging cancers worldwide. Over the past few years, new molecular-targeted agents and immunotherapy have markedly improved GC prognosis. Human epidermal growth factor receptor 2 (HER2) expression is a key biomarker in first-line chemotherapy for unresectable advanced GC. Further, the addition of trastuzumab to cytotoxic chemotherapy has extended the overall survival of patients with HER2-positive advanced GC. In HER2-negative GC, the combination of nivolumab, an immune checkpoint inhibitor, and a cytotoxic agent has been demonstrated to prolong the overall survival of GC patients. Ramucirumab and trifluridine/tipiracil, which are second- and third-line treatments for GC, and trastuzumab deruxtecan, an antibody–drug conjugate for HER2-positive GC, have been introduced in clinics. New promising molecular-targeted agents are also being developed, and combination therapy comprising immunotherapy and molecular-targeted agents is expected. As the number of available drugs increases, it is important to understand the target biomarkers and drug characteristics and select the optimal therapy for each patient. For resectable disease, differences in the extent of standard lymphadenectomy between Eastern and Western countries have led to different standard treatments: perioperative (neoadjuvant) and adjuvant therapy. This review aimed to summarize recent advances in chemotherapy for advanced GC.