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Chapter 087. Gastrointestinal Tract Cancer (Part 3)

Tumors of the Stomach Gastric Adenocarcinoma Incidence and Epidemiology For unclear reasons, the incidence and mortality rates for gastric cancer have decreased markedly during the past 75 years. The mortality rate from gastric cancer in the United States has dropped in men from 28 to 5.8 per 100,000 persons, while in women the rate has decreased from 27 to 2.8 per 100,000. Nonetheless, 21,260 new cases of stomach cancer were diagnosed in the United States, and 11,210 Americans died of the disease in 2007. Gastric cancer incidence has decreased worldwide but remains high in Japan, China, Chile, and Ireland. The risk of gastric cancer. | Chapter 087. Gastrointestinal Tract Cancer Part 3 Tumors of the Stomach Gastric Adenocarcinoma Incidence and Epidemiology For unclear reasons the incidence and mortality rates for gastric cancer have decreased markedly during the past 75 years. The mortality rate from gastric cancer in the United States has dropped in men from 28 to 5.8 per 100 000 persons while in women the rate has decreased from 27 to 2.8 per 100 000. Nonetheless 21 260 new cases of stomach cancer were diagnosed in the United States and 11 210 Americans died of the disease in 2007. Gastric cancer incidence has decreased worldwide but remains high in Japan China Chile and Ireland. The risk of gastric cancer is greater among lower socioeconomic classes. Migrants from high- to low-incidence nations maintain their susceptibility to gastric cancer while the risk for their offspring approximates that of the new homeland. These findings suggest that an environmental exposure probably beginning early in life is related to the development of gastric cancer with dietary carcinogens considered the most likely factor s . Pathology About 85 of stomach cancers are adenocarcinomas with 15 due to lymphomas and gastrointestinal stromal tumors GIST and leiomyosarcomas. Gastric adenocarcinomas may be subdivided into two categories a diffuse type in which cell cohesion is absent so that individual cells infiltrate and thicken the stomach wall without forming a discrete mass and an intestinal type characterized by cohesive neoplastic cells that form glandlike tubular structures. The diffuse carcinomas occur more often in younger patients develop throughout the stomach including the cardia result in a loss of distensibility of the gastric wall so-called linitis plastica or leather bottle appearance and carry a poorer prognosis. Intestinal-type lesions are frequently ulcerative more commonly appear in the antrum and lesser curvature of the stomach and are often preceded by a prolonged precancerous process. While the .