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Gastric Lymphoma

Traditionally patients with a gastric lymphoma were treqated with surgery (often a gastrectomy or removal of the whole stomach).

Now there are two common types of gastric lymphoma. With a less aggressive forms of lymphoma called MALT (see below).  These patients are usually treated with chemotherapy or antibiotics (for gastric lymphomas if related to the infection with heliobacter) but radiation can be used (see NCCN flow chart and NCCN guidelines page 1 and page 2) see studies on radiation for gastric lymphoma.)

For more aggressive lymphomas (like diffuse large B cell lymphoma) chemotherapy is generally indicated often followed by gastric radiation or if the patient is not a candidate for chemotherapy, then radiation alone to the stomach may be appropriate.

Treatment for non-gastric MALT go here for a general   discussion of MALT see below:

 
The diminishing role of surgery in the treatment of gastric lymphoma

Department of Surgery, Massachusetts General Hospital, Boston, Massachusetts


Primary gastric lymphomas are non-Hodgkin lymphomas that originate in the stomach and are divided into low-grade (or indolent) and high-grade (or aggressive) types. Low-grade lesions nearly always arise from mucosa-associated lymphoid tissue (MALT) secondary to chronic Helicobacter pylori (H. pylori) infection and disseminate slowly. High-grade lesions may arise from a low grade-MALT component or arise de novo and can spread to lymph nodes, adjacent organs and tissues, or distant sites. Methods:

About 40% of gastric lymphomas are low-grade, and nearly all these low-grade lesions are classified as MALT lymphomas. For low-grade MALT lymphomas confined to the gastric wall and without certain negative prognostic factors, H. pylori eradication is highly successful in causing lymphoma regression. More advanced low-grade lymphomas or those that do not regress with antibiotic therapy can be treated with combinations of H. pylori eradication, radiation therapy, and chemotherapy.

Nearly 60% of gastric lymphomas are high-grade lesions with or without a low-grade MALT component. These lymphomas can be treated with chemotherapy and radiation therapy according to the extent of disease. Surgery for gastric lymphoma is now often reserved for patients with localized, residual disease after nonsurgical therapy or for rare patients with complications.

MALT (see discussion below and the NCI discussion.) These are classified under the indolent lymphoma group: Marginal zone lymphomas were previously included among the diffuse small lymphocytic lymphomas. When marginal zone lymphomas involve the nodes, they are called monocytoid B-cell lymphomas, and when they involve extranodal sites (gastrointestinal tract, thyroid, lung, breast, skin), they are called mucosa-associated lymphatic tissue (MALT) lymphomas. Many patients have a history of autoimmune disease, such as Hashimoto's thyroiditis or Sjogren's syndrome, or of Helicobacter gastritis. Most patients present with stage I or II extranodal disease, which is most often in the stomach. Treatment of Helicobacter pylori infection may resolve many cases of localized gastric involvement. After standard antibiotic regimens, 50% of patients show resolution of gastric MALT by endoscopy after 3 months. Other patients may resolve after 12 to 18 months of observation.

Extranodal B-Cell Lymphoma of MALT

MALT lymphomas are usually localized, and are seen most frequently in the stomach, lung, salivary gland, thyroid, and lacrimal gland.They may, less often, involve the orbit, conjunctiva, breast, bladder, kidney, or thymus.Apart from a swelling in the relevant area (in the case of salivary gland tumors), patients may be otherwise asymptomatic; these are slow-growing tumors. Recurrence may occur at the original site or at another MALT lymphoma-associated one.

The diagnosis of MALT lymphoma is usually applied to a small cell lymphoma. However, MALT lymphomas can undergo histologic progression to a large cell lymphoma. The term high-grade MALT is sometimes used to describe this situation. These patients should not be confused with having a typical small cell MALT lymphoma and need to be treated like any other diffuse large B-cell lymphoma. Treating a patient with a transformal MALT lymphoma of the stomach with antibiotics would be a tragedy.

There is an association with autoimmune diseases: for example, MALT lymphomas of salivary glands are associated with Sjogren's syndrome; MALT lymphoma of the thyroid is associated with Hashimoto's thyroiditis. The development of gastric MALT lymphomas has been attributed to antigenic stimulation associated with chronic Helicobacter pylori gastritis.Indeed, standard treatment for early-stage disease is now antibiotic therapy to eradicate the infection regression of lymphoma occurs in some patient

Management

Surgical excision is the primary treatment (and in most cases is required to make the diagnosis). Further treatment may not be needed. Where the tumor has been incompletely excised, radiotherapy may be appropriate. Some would use adjuvant radiotherapy.

In the few patients who present with more widespread disease, systemic chemotherapy is effective; the precise regimen will depend on the pathology. The majority of MALT lymphomas respond to treatment as for follicular lymphoma (e.g., chlorambucil). However, evolution to DLBC lymphoma can occur when an Adriamycin-containing regimen is necessary.Further details about management are included in relation to specific sites of extranodal lymphoma.

Gastric Lymphoma

Since many patients present with symptoms that may lead directly to laparotomy, gastrectomy may have been performed before a definitive diagnosis was made. However, with the widespread use of endoscopy, most physicians would now agree that an operation is not necessary and, in view of the problems experienced after gastrectomy, to be avoided if possible. The published literature suggests that as many as 50 percent of those in whom lymphoma is low grade and confined to the stomach may achieve prolonged remissions induced by surgery alone. Adjuvant chemotherapy, the details of which will be determined by the grade of the lymphoma, appears to increase the cure fraction, as does irradiation.

As mentioned above it has now been demonstrated that antibiotic therapy for Helicobacter infection can result in regression of primary B-cell gastric MALT lymphoma. Treatment comprises ampicillin with either metronidazole and tripotassium dicitrobismuthate or omeprazole.This poses the question as to whether eradication of H. pylori will suffice as treatment for selected patients with early-stage lymphoma of the stomach.

An epidemiologic association has also now been found. It is proposed that treatment with antibiotics withdraws the H. pylori antigenic stimulus at an early stage of clonal B-cell proliferation, and that this may in turn arrest the malignant process, before it becomes irreversible. However, questions remain. H. pylori is a ubiquitous bacterial infection; it has to be assumed that gastric MALT lymphoma will only develop in a very small percentage of such patients. The incidence in the United States is between 1 in 3,000 and 1 in 8,000, although a higher incidence has been reported in the northeast of Italy. Presumably, additional environmental or host-related factors are needed to result in lymphoma. There is also the question: At what point should H. pylori infection be treated?

Patients with DLBC gastric lymphomas are almost invariably treated with chemotherapy or combined-modality therapy, with rather worse results than those with low-grade lymphoma. Important prognostic factors are local and distant spread, as well as invasion of local vital organs, particularly the liver and pancreas.