Gastric cancer is a major global health burden, especially when patients are diagnosed with recurrent or metastatic
gastric cancer. Despite recent advances in treatment options with palliative
chemotherapy, the median overall survival of patients with
gastric cancer remains within 1 or 2 years after the diagnosis of metastatic disease.
Gastric cancer is significantly more prevalent in eastern Asia (e.g., Japan and Korea). Next-generation sequencing (NGS) is rapidly being adopted as part of clinical practice in Korea and Japan, especially in patients with
gastric cancer. Approximately 10% to 15% of the patients with
gastric cancer who undergo NGS of their
tumor specimen are allocated to target-matched clinical trials in Japan and Korea. In Japan and Korea, a
cell-free DNA NGS panel is also actively being investigated as an alternative NGS test for patients with
gastric cancer, which may reflect the
tumor heterogeneity of
gastric cancer. In Japan and Korea, multiple
biomarkers, such as HER2, mismatch repair, Epstein-Barr virus, PD-L1 (combined positive score), EGFR, FGFR2, and CLDN18.2, are routinely assessed through immunohistochemistry or in situ hybridization before initiation of the first-line treatment in all patients with
gastric cancer. Most tertiary
cancer centers in Korea routinely perform HER2, mismatch repair, Epstein-Barr virus, and PD-L1 NGS before palliative
chemotherapy in patients with
gastric cancer.
Biomarker evaluation for all patients with metastatic
gastric cancer enables clinicians to identify available
biomarker-based clinical trials early during the course of treatment, which expands treatment opportunities while patients are medically fit for clinical trials, if available. Comprehensive genomic profiling using a tissue or
circulating tumor DNA NGS panel is considered necessary during second-line or subsequent treatment. It is hoped that a comprehensive molecular profiling strategy will facilitate greater use of
precision medicine through molecularly targeted
therapies for patients with
gastric cancer in the near future.