Changing landscape in stage, treatment and survival of gastric cancer in China 1998-2022: Insights of 40,158 patients from the National Gastric Cancer Cohort.

[INTRODUCTION] Assessing progress in cancer control at the national level is crucial, as it offers key insights into the overall effectiveness of the health system. Here, we aimed to describe 20-year trends in stage distribution, treatment patterns, and survival for gastric cancer in China, and to estimate stage- and treatment-specific 1-, 3-, 5-, and 10-year overall survival (OS) at the national level.

[METHODS] In this study, we included data from 40,158 patients diagnosed with gastric cancer between 1998 and 2022, derived from nine tertiary grade-A hospitals located across all four major regions of China. The characteristics, treatment modalities, and survival outcomes were analyzed across four predefined time periods: period 1 (1998-2005), period 2 (2006-2010), period 3 (2011-2015), and period 4 (2016-2022). Stage- and treatment-specific survival with 95 % confidence intervals (CIs) was estimated using the Kaplan-Meier method; differences were assessed by log-rank test.

[RESULTS] During the study period, there was an increasing proportion of patients with early stage gastric cancer from 9.8 % in 1998 to 19.5 % in 2022, while patients with metastatic disease remained stable. For early gastric cancer classified as cT1aN0, the proportion of patients undergoing endoscopic resection increased from 0.0 % in period 1-30.4 % in period 4. Among patients with locally advanced gastric cancer, the proportion receiving neoadjuvant therapy increased from 0.8 % to 17.3 %. Regarding survival outcomes, the 5-year OS rate of gastric cancer cohort increased from 38.2 % in period 1-46.1 % in period 4. Stage-specific 5-year OS rates were 90.0 % (stage I), 69.0 % (stage II), 37.0 % (stage III), and 13.7 % (stage IV). Compared with Japan, gastric cancer patients with stage IA in China exhibited higher 5-year OS rate (91.9 % vs. 89.6 %) but a much lower proportion (16.9 % vs. 43.6 %). Survival for stage IIIA-IIIC was poorer in China (48.5 % vs. 59.3 %, 34.7 % vs. 45.6 %, 21.8 % vs. 29.9 %; respectively).

[CONCLUSIONS] From 1998 to 2022, the proportion of patients diagnosed with early-stage gastric cancer in China gradually increased, and treatment strategies changed substantially over time, accompanied by a modest improvement in the 5-year OS rate. The disparities in stage distribution and survival outcomes between China and Japan highlight the need to further improve early detection of gastric cancer and to develop more effective treatment modalities for patients with stage III disease in China.