The Effect of Neoadjuvant Therapies for Patients with Locally Advanced Gastric Cancer: A Propensity Score Matching Study

Background: The aim of this study was to evaluate the effect of neoadjuvant therapies (NAT) on patients with locally advanced gastric cancer (LAGC). Methods: This study retrospectively analyzed LAGC patients treated at the China National Cancer Center between October 2006 and December 2018. All patients included were divided into two groups, NAT followed by surgery (NAT-Surgery) and adjuvant chemotherapy following surgery (Surgery-ACT). Subgroup analysis compared between patients underwent either neoadjuvant chemotherapy (nCT) or neoadjuvant chemoradiation (nCRT) was conducted. Propensity score matching (PSM) was implemented to reduce selection bias. Results: In total, 2779 patients were included in this study (494 of NAT-Surgery group and 2285 of Surgery-ACT group). After PSM, the patients in NAT-Surgery group had a significantly longer overall survival (OS) than patients in Surgery-ACT group (P<0.001). Subgroup analysis revealed that grade 3 or 4 adverse events were more frequently observed in nCRT group during neoadjuvant treatment (52.0% in nCRT group vs. 34.0% in nCT group, P=0.010). Pathological complete response (pCR) being achieved in 17.0% after nCRT versus 4.0% after nCT (P<0.001). Patients of the nCRT group obtained better disease-free survival (DFS, P=0.024) and local-recurrence-free survival (LRFS, P=0.014) than patients in nCT group, while there was no significant difference in OS between the two groups. Conclusions: In conclusion, NAT improved survival outcomes among LAGC patients over surgery followed by adjuvant chemotherapy. In comparison with nCT, nCRT resulted in higher pCR rate, better DFS and LRFS, without significantly affecting OS.