tailieunhanh - Chapter 087. Gastrointestinal Tract Cancer (Part 4)

Several additional etiologic factors have been associated with gastric carcinoma. Gastric ulcers and adenomatous polyps have occasionally been linked, but data on a cause-and-effect relationship are unconvincing. The inadequate clinical distinction between benign gastric ulcers and small ulcerating carcinomas may, in part, account for this presumed association. The presence of extreme hypertrophy of gastric rugal folds (., Ménétrier's disease), giving the impression of polypoid lesions, has been associated with a striking frequency of malignant transformation; such hypertrophy, however, does not represent the presence of true adenomatous polyps. . | Chapter 087. Gastrointestinal Tract Cancer Part 4 Several additional etiologic factors have been associated with gastric carcinoma. Gastric ulcers and adenomatous polyps have occasionally been linked but data on a cause-and-effect relationship are unconvincing. The inadequate clinical distinction between benign gastric ulcers and small ulcerating carcinomas may in part account for this presumed association. The presence of extreme hypertrophy of gastric rugal folds . Menetrier s disease giving the impression of polypoid lesions has been associated with a striking frequency of malignant transformation such hypertrophy however does not represent the presence of true adenomatous polyps. Individuals with blood group A have a higher incidence of gastric cancer than persons with blood group O this observation may be related to differences in the mucous secretion leading to altered mucosal protection from carcinogens. A germline mutation in the E-cadherin gene inherited in an autosomal dominant pattern and coding for a cell adhesion protein has been linked to a high incidence of occult gastric cancers in young asymptomatic carriers. Duodenal ulcers are not associated with gastric cancer. Clinical Features Gastric cancers when superficial and surgically curable usually produce no symptoms. As the tumor becomes more extensive patients may complain of an insidious upper abdominal discomfort varying in intensity from a vague postprandial fullness to a severe steady pain. Anorexia often with slight nausea is very common but is not the usual presenting complaint. Weight loss may eventually be observed and nausea and vomiting are particularly prominent with tumors of the pylorus dysphagia and early satiety may be the major symptoms caused by diffuse lesions originating in the cardia. There are no early physical signs. A palpable abdominal mass indicates long-standing growth and predicts regional extension. Gastric carcinomas spread by direct extension through the gastric wall