Results: A total of 403 Thai and 2,318 Japanese patients were retrieved from the electronic database. Finally, 332 Thai and 414 Japanese patients (randomly sampled) with gastric adenocarcinoma were eligible for analysis. Thai gastric adenocarcinoma patients were significantly younger than the Japanese (59 ± 13 vs. 68 ±10 years old, p<0.001) and the majority of Thai patients were female (55% vs. 25%, p<0.001). The rate of smoking (5.1% vs. 23%, p<0.001) and alcohol drinking (2.7% vs. 34%, p<0.001) were lower in Thai patients when compared with those in Japanese. The mortality rate at the conclusion of this study (July 2016) was significantly higher in Thai patients (75.3% vs. 7%, p<0.001). In multivariate analysis, ethnicity, clinical UICC stage II-IV compared to I, and resection-based treatment were significant prognostic factors after adjusting for age, gender, presence of alarm symptom, lesion extension and histology.
Conclusion: Thai patients with gastric adenocarcinoma were different from Japanese patients in all aspects. Advanced stage of disease, country, and un-resected tumor were associated with poor prognosis. An individual strategy to improve survival of gastric adenocarcinoma in a low-prevalence area such as Thailand should be explored.