Purpose of This Summary
This PDQ cancer information summary for health professionals provides comprehensive, peer-reviewed, evidence-based information about the treatment of childhood ependymoma. It is intended as a resource to inform and assist clinicians who care for cancer patients. It does not provide formal guidelines or recommendations for making health care decisions.
Reviewers and Updates
This summary is reviewed regularly and updated as necessary by the PDQ Pediatric Treatment...
The age-adjusted incidence rate for gastric cancer in the United States for the years 2004 to 2008 was 7.7 persons per 100,000 population. Incidence among men is twice as high as among women. Mortality rates for gastric cancer have been declining worldwide in recent decades, most prominently in the United States.[2,3] Mortality rates for white males in the United States were approximately 40 deaths per 100,000 population in 1930, compared with 4.6 deaths per 100,000 population for the years 2003 to 2007. The death rate from gastric cancer for black males was 2.3 times higher than for whites for the years 2003 to 2007. The annual number of new cases seems to be steady in recent years; in 2013, it is estimated 21,600 Americans will be diagnosed with gastric cancer and 10,990 persons will die of it. Gastric cancer is the fourth most common cancer in the world.[6,7] Worldwide, the estimated number of cases per year in 2008 was 988,000, and the estimated number of deaths was 736,000. Age-standardized annual incidence rates vary widely across the world: from 3.9 to 42.4 cases per 100,000 in men, and from 2.2 to 18.3 cases per 100,000 in women. More than 70% of cases occur in developing countries, and 50% of the cases occur in Eastern Asia.
Most cancers in the United States are advanced at diagnosis, which is reflected in an overall 5-year survival rate of 27.1% from 2001 to 2007. Carcinomas localized to the mucosa or submucosa ("early" cancers) have a much better prognosis; the 5-year survival rate is more than 95% in Japan and more than 65% in the United States. In high-risk populations, secondary prevention measures linked to screening programs have been instituted. In Japan, endoscopic resection techniques have been refined and could possibly be responsible for drastic reductions in mortality rates in the presence of steady incidence rates. This hypothesis, however, has not been tested in clinical trials. (Refer to the PDQ summary on Stomach (Gastric) Cancer Screening for more information.)
Understanding the pathogenesis of gastric cancer has advanced over the years. A lengthy precancerous process has been identified in which the gastric mucosa is slowly transformed from normal to chronic gastritis, to multifocal atrophy, to intestinal metaplasia of various degrees, to dysplasia, and then to invasive carcinoma. The process is apparently driven by forces acting on the gastric epithelium for many years, such as excessive dietary salt and most prominently, infection with H. pylori.
Interventions for Reduction of Stomach (Gastric) Cancer Risk
A systematic review and meta-analysis showed a 60% increase in gastric cancer in male smokers and a 20% increase in gastric cancer in female smokers compared with nonsmokers. A systematic review of studies addressing the relationship between cigarette smoking and gastric cancer to estimate the magnitude of the association for different levels of exposure to cancer provides solid evidence to classify smoking as the most important behavioral risk factor for gastric cancer.[10,11,12] Compared with persistent smokers, the risk of stomach cancer decreases among former smokers with time since cessation. The pattern that emerges from these observations makes it reasonable to infer that cigarette smoking prevention or cessation would result in a decreased risk of gastric cancer.