Abstract
BACKGROUND: Brain metastases (BM) are very rare in gastric adenocarcinoma (GaC), and patients with BMs have a higher mortality rate due to stronger tumor aggressiveness. However, its pathogenesis remains unclear. Genetic testing revealed cellular-mesenchymal epithelial transition factor receptor (MET) amplification. Therefore, treatment with savolitinib, a small molecule inhibitor of c-Met, was selected. CASE SUMMARY: A 66-year-old woman was diagnosed with advanced GaC 6 months prior to presentation due to back pain. Cerebellar and meningeal metastases were observed during candonilimab combined with oxaliplatin and capecitabine therapy. The patient experienced frequent generalized seizures and persistent drowsiness in the emergency department. Genetic testing of cerebrospinal fluid and peripheral blood revealed increased MET amplification. After discussing treatment options with the patient, savolitinib tablets were administered. After a month of treatment, the intracranial lesions shrank considerably. CONCLUSION: BM is very rare in advanced GaC, especially in meningeal cancer, that is characterized by rapid disease deterioration. There are very few effective treatment options available; however, technological breakthroughs in genomics have provided a basis for personalized treatment. Furthermore, MET amplification may be a key driver of BM in gastric cancer; however, this conclusion requires further investigation.