Outcomes of patients with nonmetastatic gastric adenocarcinoma according to perioperative treatment strategy: a real-world, population-based study.

Aim: To assess the survival outcomes of patients with nonmetastatic gastric cancer according to the type of perioperative treatment strategy used (surgery-only, adjuvant chemo-radiotherapy, adjuvant chemotherapy, perioperative chemotherapy) in a population-based setting. Materials & methods: Surveillance, Epidemiology and End Results research-plus database was explored, and patients with nonmetastatic gastric cancer who were treated with an oncologic surgery were reviewed. Multivariable Cox regression analysis was used to examine the impact of treatment strategy on overall and cancer-specific survival. Results: A total of 11,526 patients were found to be eligible and they were included in the current analysis. Looking at the percentages of different treatment strategies throughout the study years (2006-2017), the use of the following strategies increased: adjuvant chemotherapy (20.1 vs 10.6%), and perioperative chemotherapy (21.3 vs 0.5%); while the use of the following strategies decreased: surgery only (36.2 vs 58.2%), and adjuvant chemo-radiotherapy (22.4 vs 30.6%). Using multivariable Cox regression analysis, the following factors were associated with worse overall survival: older age (hazard [HR]: 1.021; 95% CI: 1.018-1.023), males (HR: 1.09; 95% CI: 1.04-1.14), Black race (HR: 1.11; 95% CI: 1.04-1.19), cardia subsite (HR: 1.09; 95% CI: 1.02-1.17), grade 3-4 (HR:1.32; 95% CI: 1.25-1.40), diffuse histology (HR: 1.46; 95% CI: 1.35-1.58), clinically node positive (HR:1.43; 95% CI: 1.34-1.53), total gastrectomy (HR: 1.20; 95% CI: 1.13-1.28), and surgery-only approach (HR: 1.65; 95% CI: 1.55-1.75). Conclusion: Among patients with localized gastric cancer, patients who were treated with surgery-only, and to a less extent, patients who were treated with surgery followed by adjuvant chemotherapy have worse survival outcomes; while those treated with perioperative chemotherapy have the best survival outcomes.