Comparison in pathological behaviours & prognosis of gastric cancers from general hospitals between China & Japan.

BACKGROUND & OBJECTIVES Gastric cancer is the fourth most common cancer and the second leading cause of cancer-related deaths after lung carcinoma. The aim of this study was to understand the difference in clinicopathological behaviours and prognosis of gastric cancer in patients from China and Japan. METHODS Paraffin-fixed tissue samples of gastric cancer were collected retrospectively from two hospitals between 1993 to 2006 in Japan (n=2063) and during 1980-2003 in China (n=2496) respectively, and staging was done by TNM system and typing by Japanese Endoscopy Society criteria or Borrmann's classification. The histological architecture of the tumours was expressed according to Lauren's classification. RESULTS Compared to Japan, the occurrence of gastric cancer was more common in younger Chinese population and prone to invasion and metastasis in muscularis propia, lymphatic, lymph node, liver, peritoneal parts, and exhibited large tumour size and high TNM staging in both the sexes and in different age groups (P<0.05). Intestinal and mixed types of carcinomas were more frequently observed in Japanese patients compared to Chinese and the difference was significant (P<0.05). It was observed that the commonly reported types in early gastric cancers (EGC) in Japanese patients were IIc, IIa+IIc or IIa while those of Chinese patients were IIc, III or IIb. In the case of advanced gastric cancers (AGC), type II and III were most common in both the countries. The cumulative survival rate of Chinese patients was significantly (P<0.05) higher compared to Japanese in different stratified groups via depth of invasion, TNM staging or Lauren's classification. INTERPRETATION & CONCLUSION Gastric cancers in Chinese patients had more aggressive pathological characteristics and poorer prognosis than those from Japan. To reduce incidence and to improve treatment facilities, it is necessary to have a systematic screening system.