Durable Complete Remission of Metastatic Gastric Cancer Following Platinum-Based Chemotherapy: A Case Report.

Gastric cancer is a common type of gastrointestinal tract malignancy. It is characterized by a poor prognosis - median survival for metastatic disease is about 12 months. A small percentage of gastric cancer is characterized by high sensitivity to systemic treatment, resulting in deep and durable responses. Predictors for such hyper-responses are still under investigation, and a wide variety of possible mechanisms exist, including the DNA damage response, intracellular signaling, immune engagement, genetic alterations, and the tumor microenvironment. Here we present a case of a 59-year-old patient with human epidermal growth factor receptor-2 (HER-2)-negative, programmed death ligand-1 (PD-L1) negative, mismatch repair proficient (pMMR) metastatic gastric cancer who reached a particularly long progression-free survival (PFS) exceeding 93 months.