Overview of the Epidemiology and Treatment of Gastric Cancer

Abstract

The incidence and mortality rates for gastric cancer have decreased in the developed countries for the last several decades. On the other hand, they remain high in far Eastern countries such as Japan, China, and Korea and also in many developing countries. The risk of gastric cancer is greater among lower socioeconomic classes. The causes of this disease are still unclear. Long-term ingestion of highly concentrated nitrates in dried, smoked, and salted foods might be related with higher risk. Helicobacter pylori infection was classified as a group I definite human gastric carcinogen by the International Agency for Research on Cancer, World Health Organization (IARC/WHO) in1994. However, there are some debates on the association between H. pylori infection and gastric cancer. Complete surgical removal of the tumor with resection of adjacent lymph nodes offers the only chance for cure. As yet, this kind of treatment is possible in less than a half of patients. The prognosis after complete surgical resection depends on the degree of tumor penetration to the gastric wall. Cases with regional lymph node involvement, vascular invasion,and abnormal DNA content show poor prognosis. Gastric carcinoma is a relatively radio-re-sistant tumor, and the major role of radiation therapy has been the palliation of pain. Combinations of cytotoxic drugs for patients with advanced gastric cancer have shown a partial response in 20~60% of the patients, however, and complete remission was rare. In some recent studies, chemotherapy plus irradiation after surgical resection showed a better disease-free survival and overall survival. In conclusion, early detection and curative resection are very important to improve the survival of patients with gastric cancer. Newer therapeutic strategies such as preoperative chemotherapy or chemoradiotherapy have the potential to benefit the high-risk patients.