Long-Term Outcomes of Neoadjuvant Chemotherapy in Locally Advanced Gastric Cancer/Esophagogastric Junction Cancer: A Systematic Review and Meta-Analysis

Background: Neoadjuvant chemotherapy (NAC) has been defined as any preoperative chemotherapy scheme aiming to reduce tumor staging and to control preoperative micrometastasis, which has been extensively used as a treatment for resectable gastric cancer. However, its effect on the long-term survival of patients with locally advanced gastric cancer (AGC) or esophagogastric junction cancer (EGC) remains unknown. Objective: This study aimed at investigating the long-term efficacy of NAC in locally AGC/EGC. Methods: The following databases were searched for articles published from their inception to April 2020: PubMed, Web of Science, EBSCO, and Cochrane library. The primary outcomes were overall survival (OS) and progression-free survival (PFS). Results: A total of 19 articles were included in this meta-analysis, with a total of 4,446 patients. The results showed that NAC increased the patients’ 3-year OS (HR: 0.56, 95% CI, 0.21 - 0.91, p < 0.001), 3-year PFS (HR: 0.76, 95% CI, 0.66 - 0.87, p < 0.001), 5-year OS (HR: 0.71, 95% CI, 0.64 - 0.78, p < 0.001), and 5-year PFS (HR: 0.70, 95% CI, 0.61 - 0.79, p < 0.001). Besides, subgroup analysis showed that Asian countries have benefited significantly from NAC (HR: 0.65, 95% CI, 0.55 - 0.74, p < 0.001), and other countries have also benefited (HR: 0.79, 95% CI, 0.68 - 0.89, p < 0.001). Conclusions: Compared with adjuvant chemotherapy and surgery alone, NAC can improve the long-term survival outcomes (OS and PFS) of patients with resectable AGC or EGC.