Prognostic impact of surgical resection after chemotherapy in oligometastatic versus non-oligometastatic gastric cancer

BACKGROUND: Surgical resection following chemotherapy has been considered a potentially effective strategy for improving survival in patients with stage IV gastric cancer. Recently, the concept of oligometastasis has gained increasing attention. However, the prognostic significance of surgical resection according to oligometastatic status remains unclear, particularly in comparison with non-oligometastatic disease. METHODS: We retrospectively reviewed 249 patients with stage IV gastric cancer who received systemic chemotherapy. Patients were classified into an oligometastatic group (n = 52) or a non-oligometastatic group (n = 197) based on the extent of distant metastases. Overall survival (OS) was analyzed according to metastatic status and the performance of surgical resection. RESULTS: Surgical resection after chemotherapy was performed in 27 (52%) patients in the oligometastatic group and in 47 (24%) patients in the non-oligometastatic group, with a significantly higher rate of surgery in the oligometastatic group (p < 0.01). Median OS was significantly longer in the oligometastatic group than in the non-oligometastatic group (p < 0.01). OS was significantly better in patients who underwent surgery after chemotherapy than in those who did not (p < 0.01). However, among patients who underwent surgery, there was no significant difference in OS between the oligometastatic and non-oligometastatic groups (p = 0.29). Multivariate analysis identified peritoneal metastasis and surgical resection as independent prognostic factors (all p < 0.01). CONCLUSION: Favorable survival outcomes were observed in patients with oligometastatic gastric cancer and in selected patients with non-oligometastatic disease without peritoneal metastasis who underwent surgical resection after chemotherapy.