Survival disparities and predictors in gastric cancer: a population-based study from Kazakhstan (2012-2023).

Introduction: Gastric cancer remains a major global health burden, with Central Asia, Kazakhstan in particular, exhibiting high incidence and mortality. There is a lack of recent national data providing a detailed clinical picture of gastric cancer. Most reports have been limited to summary statistics on incidence or mortality, without stratification by tumor stage, histological subtype, survival, or associated comorbidities. This study addresses gaps by using national registry data to evaluate 12-year gastric cancer trends, patient characteristics, and outcomes. We aim to investigate gastric cancer epidemiology, survival, and associated risk factors in Kazakhstan for the prevention and control strategies. Methods: This retrospective cohort study analyzed 33,992 patients with gastric cancer using the Unified National Electronic Healthcare System in Kazakhstan from 2012 to 2023. Cases were identified via ICD-10 codes (C16.0-C16.9). Demographic, staging, histological, treatment and comorbidity data were extracted. Outcomes included incidence, mortality, and survival. Kaplan-Meier analysis and Cox regression were used to evaluate survival differences and predictors. Population-based rates were age-standardized using WHO standards. Results: The age-standardized incidence rate declined from 17.46 to 13.63 per 100,000; mortality dropped from 16.16 to 8.74. Prevalence doubled over 12 years. Most cases (33.5%) were diagnosed at Stage III, closely followed by Stage II and Stage IV. One- and five-year survival rates were 38.1% and 17.1%, respectively. Men and patients aged 60-69 had the highest incidence. Survival declined sharply with stage: Stage I (49.1%) vs Stage IV (3.5%, P < 0.001). The most common tumor site was the cardia, and adenocarcinoma was the predominant histology. Cox regression identified older age (HR 1.17 per decade), advanced stage (HR 3.48 for Stage IV), recurrence, metastases and cancer complications as significant mortality predictors (all P < 0.001). Cardiovascular and gastrointestinal diseases were the most common comorbidities. Conclusion: Gastric cancer in Kazakhstan shows late-stage diagnosis and poor survival. Targeted screening, earlier diagnosis, and improved management of comorbidities are essential to improve outcomes and reduce mortality.