– Most malignant lesions of the stomach are adenocarcinomas (95%). The rest are lymphomas and leiomyosarcomas.
Causes and Incidence
The cause of stomach cancer is unknown but is thought to be related to dietary factors connected to food preservation and preparation. Gastritis, gastric atrophy, and genetic factors are believed to be predisposing factors. The incidence varies worldwide. Stomach cancer is the most common malignancy in Japan, and the incidence is extremely high in Iceland and Chile. The number of cases has declined significantly in western Europe and the United States. About 23,000 new cases are seen in the United States each year. The incidence is higher in men (2:1 ratio), in individuals 50 to 70 years of age, and in people of lower socioeconomic status.
Cancer cells usually begin to grow in the distal end of the stomach in the lesser curvature. The cells form a tumor that spreads along the mucosa, eventually invading and moving through the stomach wall. The tumor then spreads directly to surrounding structures such as the spleen, esophagus, pancreas, colon, duodenum, and peritoneum. The cancer is also spread via the lymphatics to regional nodes and via the bloodstream to the liver.
No specific symptoms appear in the early stages. Most people have generalized gastrointestinal (GI) complaints such as indigestion, burping, and fullness after eating. Later signs may include vomiting, dysphagia, anorexia, weight loss, and back pain.
The prognosis for long-term survival is poor (16%), primarily because most cases are diagnosed after metastasis has occurred. Complications include malnutrition and GI obstruction.
Double-contrast x-ray studies of the stomach can delineate suspicious lesions. The definitive diagnosis is made by endoscopy with brush biopsy.
Excision of the tumor and regional lymph nodes; subtotal or total gastric resection or gastrectomy for resection for cure, depending on tumor location; gastroenterostomy for palliation.
Systemic chemotherapy to treat advanced metastatic disease.
Radiation for palliation of GI obstruction.