surgical removal of all or part of the stomach. This procedure is used to remove both benign and malignant neoplasms (tumours (tumour)) of the stomach, including adenocarcinoma and lymphoma of the stomach. A variety of less-common benign tumours of the stomach or stomach wall can also be successfully treated with partial gastrectomy. In addition, the operation is sometimes used to treat peptic ulcers (peptic ulcer) because it eliminates the gastric-acid-secreting parietal cells in the stomach lining and halts the production of the acid-stimulating hormone gastrin, thus removing the underlying cellular substances that give rise to an ulcer. Once a common method of treatment for patients with painful ulcers, gastrectomy is now used only as a last resort if the appropriate drugs have failed or if an ulcer is perforated or hemorrhaging.

The most common procedure is antrectomy, which removes the lower half of the stomach (antrum), the chief site of gastrin secretion. The remaining stomach is then reconnected to the first section of the small intestine (duodenum). In a more extensive procedure, subtotal gastrectomy, as much as three-quarters of the stomach is removed, including all of the antrum. The remaining stomach may then be reattached directly to the duodenum or to the jejunum, a more distal part of the intestine beyond the usual site of ulceration.

The long-term survival rates of patients with stomach cancer who undergo gastrectomy vary widely; for example, patients with early stage cancer have high five-year survival rates, typically around 90 percent, whereas patients with late-stage cancers have low five-year survival rates, generally less than 10 percent. Gastrectomy is often accompanied by gastric lymphadenectomy (removal of lymph nodes associated with the stomach), which can improve survival rate in some stomach cancer patients. The incidence of ulcer recurrence after gastrectomy is very low (about 2 percent) when the antrum is completely removed. The most significant drawback to gastrectomy is general malnutrition, caused by decreased appetite and by the stomach's decreased ability to digest food.