Gastric lymphoma

Gastric lymphoma is an interesting disease and some aspects of the management are controversial. It is first important to distinguish primary gastric lymphoma from involvement in the stomach in a generalised lymphomatous process. This latter situation is more common than the former. Unlike gastric carcinoma, the incidence of lymphoma seems to be increasing. Primary gastric lymphoma accounts for approximately 5 per cent of all gastric neoplasms.

Gastric lymphoma is the most common in the sixth decade and the presentation is no different from gastric cancer, the common symptoms being pain, weight loss and bleeding. Acute presentations of gastric lymphoma such as haematemesis, perforation or obstruction are not common. Primary gastric lymphomas are B-cell-derived, the tumour arising from the mucosa-associated lymphoid tissue (MALT). Primary gastric lymphoma remains in the stomach for a prolonged period before involving the lymph nodes. At an early stage the disease takes the form of a diffuse mucosal thickening which may ulcerate. Diagnosis is made as a result of the endoscopic biopsy and seldom on the basis of the endoscopic features alone, which are not specific.

Following diagnosis adequate staging is necessary, primarily to establish whether the lesion is a primary gastric lymphoma or part of more generalised process. A  CT scan of the chest and abdomen and bone marrow aspirate are required, as well as a full blood count.

Although the treatment of primary gastric lymphoma is somewhat controversial, it seems most appropriate to use surgery alone for the localised disease process. No benefit has been shown from adjuvant chemotherapy, although some oncologists contend that primary gastric lymphoma can be treated by chemotherapy alone. Chemotherapy alone is appropriate for patients with systemic disease.

Some of the more controversial aspects of gastric lymphoma concern the role of H. pylori. Lymphocytes are not found to any degree in normal gastric mucosa but are found in association with Helicobacter infection. It has also been shown that early gastric lymphomas may regress and disappear when the Helicobacter infection is treated (Issacson). This is an extremely surprising finding as it suggests that the neoplasm, which is demonstrably mono­clonal, may be a response to the infective agent. It may be that the immunological response to the organism, probably a T-cell-related process, is important in maintaining the B-cell malignancy.

Gastric involvement with the diffuse lymphoma

These patients are treated with chemotherapy, sometimes with dramatic and rapid responses. Surgeons are frequently asked to deal with the complications of gastric involvement. The two common complications are bleeding and perforation. Both may occur at presentation but more usually may follow the chemotherapy when there is rapid regression and necrosis of the tumour. These operations can be technically very challenging and normally require gastrectomy.