Characteristics and epidemiology of gastric cancer in Korea: Disparity in sex and age according to histologic classification.

Abstract

21 Background: Gastric cancer (GC) is one of the most common cancers worldwide. The overall incidence of gastric cancer is higher in males, but signet ring cell carcinoma (SRC) is more common in younger females. However, the sex disparity according to the histological classification of GC in Korea has not studied much. The aim of this study is to analyze the difference of clinical manifestation between sex groups and to assess sex disparity to gastric cancer. Methods: We retrospectively analyzed 1488 patients (459 females (30.8%) and 2017 males (69.0%)) who diagnosed with gastric cancer at Korea University Ansan Hospital from 2009 to 2017. The patients were divided into three groups according to Lauren’s classification: Intestinal type GC (IGC), diffuse type GC (DGC), mixed type. The difference of clinicopathologic characteristics between these groups and sex groups were compared. Results: The age-group-specific annual incidence rates for intestinal and diffuse type GC were analyzed. The incidence of IGC increased from 40s in males. In females, the incidence of DGC was higher in young age and the proportion of IGC was increased rapidly after age 60 in females. Most of IGC appeared after age 60. (19.3% in below 60 vs. 80.7% in above 60 in females, 35.1% vs. 64.9% in males, p < 0.001) IGC seemed to appear 10-20 years earlier in male than female. Female patients were associated with poorly differentiated adenocarcinoma, SRC and DGC. Diffuse and mixed type GC was more frequent with younger, female patients and associated with advanced GC and TNM stage. Kaplan-Meier analysis revealed that the patients with IGC had a higher cumulative survival rate than those with DGC (5-year survival rate 88.2% vs. 80.5%, p < 0.001). Conclusions: Female patients with IGC were older than male patient and appeared about 10-20 years later. But this difference did not observed in DGC. Therefore, unlike DGC, sex hormones such as estrogen may act in development of IGC. This is supported by an increase of IGC in females after menopause. Further studies on role of estrogen in the development of gastric cancer are needed.