The impact of implementing current treatment modalities and female sex on gastric cancer outcomes, 2000–2016: a longitudinal nationwide cohort study

The implementation of current treatment modalities and their impact on nationwide gastric cancer outcomes remain poorly understood. Biological differences between females and males could impact survival. We aimed to analyze rates of gastric surgery, chemotherapy, and radiotherapy as well as changes in overall survival among gastric cancer patients diagnosed between 2000–2008 and 2009–2016, respectively, in Finland. Data on gastric cancer patients were collected from national registries. Cox regression analysis and the Kaplan–Meier method were used to analyze differences in survival. We identified 9223 histologically confirmed gastric cancer patients. The rate of gastric surgery decreased from 44% (<i>n</i> = 2282) to 34% (<i>n</i> = 1368; <i>p</i> &lt; 0.001). The proportion of gastric surgery patients who underwent preoperative oncological treatment increased from 0.5% (<i>n</i> = 12) to 16.2% (<i>n</i> = 222) between the calendar periods (<i>p</i> &lt; 0.001) and stood at 30% in 2016. The median overall survival (OS) improved from 30 months [95% confidence interval (CI) 28–33] to 38 months (95%CI 33–42; <i>p</i> = 0.006) and the period 2009–2016 independently associated with a lower risk of death [hazard ratio (HR) 0.78, 95%CI 0.70–0.87] among patients who underwent gastric surgery. Females exhibited a lower risk of death (HR 0.88, 95%CI 0.81–0.97) among patients who underwent gastric surgery. Preoperative oncological treatment was gradually introduced into clinical practice and OS among gastric surgery patients improved. Moreover, female surgical patients exhibited a better survival than male patients.