Clinical History:

A 61-year-old man began complaining of vague chronic abdominal pain. This was associated with a 9 kg weight loss over several months. Upper GI endoscopy revealed an irregular area of shallow ulceration on the lesser curvature of the stomach. This area was biopsied. At laparotomy, exploration of the abdomen revealed an area of diffuse, firm thickening of the gastric wall beneath the area of ulceration.

Masses of irregular glands are present extending from the mucosa into the gastric muscular wall and the serosal fat. Although these neoplastic glands seem fairly well differentiated, some irregularity along their edges is noted, and there is infiltration by inflammatory cells.

Questions:

1. What is this neoplasm?

A malignant neoplasm composed of glands is known as an adenocarcinoma. The benign version is called an adenoma.

2. Why is the cancer accompanied by weight loss?

Malignant neoplasms are often accompanied by weight loss. This may be from loss of appetite (nausea, feelings of abdominal fullness), by interference with eating or digestion (as in gastrointestinal tract neoplasms that disrupt normal function), by increased metabolic demand with a catabolic state, or by factors released by the neoplastic cells and by the body's inflammatory response to the tumor cells, such as release of cytokines such as tumor necrosis factor. In general, the greater the weight loss, the worse the prognosis.

3. How has the incidence of this disease changed in the U.S. and some other nations in this century?

Gastric adenocarcinoma has decreased in incidence in the U.S. It remains high in some parts of the world, such as Japan. This is probably a function of the extent of Helicobacter pylori infection of the stomach in the population.