Gastric MALT lymphoma is a rare type of cancer that affects the lining of the stomach. It is categorized as a low-grade non-Hodgkin lymphoma, meaning it originates from B cells. This condition develops in the mucosa-associated lymphoid tissue (MALT) in the stomach.
What is Gastric MALT Lymphoma?
Gastric MALT lymphoma arises from B cells within the marginal zone of lymphoid tissue, which is normally absent in the healthy stomach. This lymphoid tissue develops in the stomach in response to chronic antigenic stimulation, most commonly from Helicobacter pylori (H. pylori) infection. The presence of H. pylori causes long-term inflammation of the stomach lining, which can then lead to the formation of MALT and, subsequently, lymphoma.
This strong association means that H. pylori is considered a primary risk factor and often the initiating event in the development of gastric MALT lymphoma. Studies show that H. pylori infection is present in approximately 75% to 98% of gastric MALT lymphoma cases. While many people carry H. pylori, only a small percentage develop this specific type of lymphoma, suggesting other factors may also play a role.
Recognizing Symptoms and Diagnosis
Symptoms of gastric MALT lymphoma are often non-specific and can resemble common digestive issues, making early detection challenging. Patients might experience persistent indigestion, abdominal pain, nausea, or vomiting. Other symptoms can include unexplained weight loss or, in some cases, blood in the stool, which may lead to fatigue or anemia.
The diagnostic process typically begins with an upper endoscopy, where a thin, flexible tube with a camera is inserted to visualize the stomach lining. During this procedure, multiple tissue samples, known as biopsies, are collected from any suspicious areas. These biopsies are then examined under a microscope for characteristic cellular changes to confirm the diagnosis of MALT lymphoma. Testing for H. pylori infection, often through breath or stool tests, is also a routine part of the diagnostic workup due to its strong link with the condition. Staging procedures, such as CT or PET scans, are also performed to determine if the lymphoma is confined to the stomach or has spread to other areas of the body, which guides treatment decisions.
Treatment Strategies
For individuals with H. pylori-positive gastric MALT lymphoma, eradication of the bacteria is the primary and often highly effective first-line treatment. This approach commonly involves a 7- to 14-day course of antibiotics, typically a “triple therapy” regimen, combined with a proton pump inhibitor to reduce stomach acid. In cases where the initial eradication therapy fails, a “quadruple therapy” regimen can be used.
Successful H. pylori eradication can lead to complete remission of the lymphoma in a significant number of patients, with remission rates ranging from 60% to 90%. It can take several months, sometimes up to 6 to 12 months, for the lymphoma to fully regress after antibiotic treatment. For cases that do not respond to H. pylori eradication, or for H. pylori-negative lymphomas, other treatments are considered.
Low-dose involved-field radiotherapy, which precisely targets the affected area of the stomach, is an effective option for localized disease, with high complete response rates. This treatment uses low doses, minimizing side effects. Chemotherapy, often using single-agent or less intensive regimens, is generally reserved for more advanced or widespread disease, or for cases that do not respond to other treatments. The role of surgery in treating gastric MALT lymphoma is typically limited.
Life After Treatment
Long-term follow-up is a regular practice for patients who have been treated for gastric MALT lymphoma, even after achieving complete remission. This surveillance usually involves periodic endoscopic examinations with biopsies to confirm sustained remission and to monitor for any signs of recurrence.
Gastric MALT lymphoma generally has a favorable prognosis, particularly when remission is achieved after H. pylori eradication. Five-year overall survival rates are often reported to be high, sometimes exceeding 95%. While the possibility of late recurrence exists, the condition is considered treatable, and continued monitoring helps ensure any potential return of the lymphoma is detected early.