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The good news is that gastric cancer incidence rates are decreasing in Japan, which means that a smaller percentage of the population is being diagnosed with stomach cancer. The bad news is that the absolute number of people with gastric cancer is increasing due to the rapid aging of the Japanese population.¹ However, there is more good news. In Japan, gastric cancer is usually diagnosed at an early stage, resulting in improving survival rates. In fact, although gastric cancer is five times more prevalent in Japan than in the West, mortality rates are lower in Japan.²

Stomach cancer, or gastric cancer, is the growth of cancer cells in the lining and wall of the stomach. Most stomach cancers start in the mucosa, the innermost layer of the stomach. About 90 to 95% of malignant tumors of the stomach are adenocarcinomas.³ Other types of stomach cancer include lymphomas, sarcomas and other rare types. Surgery is the most common treatment for stomach cancer. Sometimes, especially in advanced cases, surgery may be combined with chemotherapy or radiation.³

There is much debate regarding the cause of stomach cancer. It is thought that a combination of hereditary and environmental factors play a part.⁵ According to the National Cancer Institute in the United States, since 1930 the incidence of gastric cancer in the U.S. has decreased four-fold, to approximately seven cases per 100,000 people.⁶ The reasons for this decrease are unknown but are believed to be related to improved food storage or dietary changes such as reduced salt intake. It is also believed that Japanese gastric cancer incidence rates are decreasing due to lifestyle and dietary changes, such as reduced salt use, increased consumption of fresh fruits and vegetables, and improved food storage.⁷ Hopefully, these changes, as well as an avoidance of smoking, will lead to both a decrease in gastric cancer incidence rates and a decrease in the absolute number of Japanese diagnosed with stomach cancer.

Discussion questions

1. Please summarize the article. What is the main point of the article?
2. If the incidence of gastric cancer is decreasing in Japan, why is the absolute number of people with gastric cancer increasing?
3. What is the most common type of stomach cancer?
4. How is stomach cancer treated?
5. What causes stomach cancer?
6. Why is the incidence of stomach cancer decreasing in Japan?

References:

1. Epidemiology of gastric cancer in Japan discussed. Cancer Weekly. 23 August 2005.
2. Stakeholder Opinions: Gastric Cancer - Targeted Therapies Home In On a Neglected Tumor Type. Datamonitor. 30 March 2006.
3. Detailed Guide: Stomach Cancer. American Cancer Society. Accessed 29 May 2006.
4. Detailed Guide: Stomach Cancer. American Cancer Society. Accessed 29 May 2006.
5. Netdoctor.co.uk. Accessed 29 May 2006.
6. Gastric Cancer (PDQR): Screening. Health Professional Version. National Cancer Institute. Last modified 23 March 2006.
7. A. Ohtsu, S. Yoshida, and N. Saijo. Disparities in Gastric Cancer Chemotherapy Between the East and West. J. Clin. Oncol., 10 May?2006; 24(14): 2188 - 2196.