Distribution of gastric adenocarcinoma subtypes in different ethnicities in Kuala Lumpur, Malaysia.

The multiracial population in Malaysia has lived together for almost a century, however, the risk of gastric cancer among them varies. This study aimed to determine the distribution of different gastric adenocarcinoma subtypes and Helicobacter pylori infection status among gastric adenocarcinoma patients. Patients with gastric adenocarcinoma were enrolled from November 2013 to June 2015. Blood samples were collected for detection of H. pylori using ELISA method. Gastric adenocarcinoma cases were more prevalent in the Chinese (52.8%), followed by the Malays (41.7%) and least prevalent in the Indians (5.6%). Gastric adenocarcinoma located in the cardia was significantly more prevalent in the Malays (66.7%) compared to the Chinese (26.3%), whereas non-cardia cancer was diagnosed more in the Chinese (73.7%) compared to the Malays (33.3%) [P = 0.019; OR = 5.6, 95 CI: 1.27 to 24.64]. The Malays also had significantly higher prevalence of gastric tumour located at the cardia or fundus than other gastric sites compared to the Chinese (P = 0.002; OR: 11.2, 95% CI: 2.2 to 56.9). Among the cardia gastric cancer patients, 55.6% of the Malays showed intestinal histological subtype, whereas all the Chinese had the diffuse subtype. More than half of the patients (55.3%) with gastric adenocarcinoma were positive for H. pylori infection and among them, 66.7% were Chinese patients. The risk of gastric adenocarcinoma in our population is different among ethnicities. Further studies on host factors are needed as it might play an important role in gastric cancer susceptibility in our population.