Marginal zone B-cell lymphoma
|Marginal zone B-cell lymphoma|
|Classification and external resources|
Marginal zone lymphomas are a group of indolent (slow-growing) NHL (non-Hodgkin lymphoma) B-cell lymphomas, which account for approximately 12 percent of all B-cell lymphomas. The median age for diagnosis is 65 years old. It presents primarily in sites such as stomach, bowel, salivary glands, lung, thyroid, lacrimal gland, conjunctiva, bladder, kidney, skin, soft tissue, thymus, breast.
- GI tract most is the most commonly involved. Within GI tract, stomach is involved in 85% cases.
There are three types of marginal zone lymphoma:
Extranodal marginal zone lymphoma or mucosa-associated lymphoid tissue (MALT) lymphoma is the most common form of marginal zone lymphoma. It occurs outside the lymph nodes, This form of lymphoma makes up about nine percent of all B-cell lymphomas.
In many cases of MALT lymphoma, patient has a previous medical history of inflammation or autoimmune disorders. For example, Helicobacter pylori (H. pylori), a microbial pathogen linked to chronic gastritis, has been associated with a significant portion of patients with gastric MALT lymphoma.
Nodal marginal zone lymphoma (sometimes called monocytoid B-cell lymphoma) occurs within the lymph nodes and accounts for about two percent of all B-cell lymphomas.
Splenic marginal zone lymphoma occurs most often in the spleen and blood. It has been associated with Hepatitis C. This form of lymphoma makes up about one percent of all B-cell lymphoma
The type of treatment selected depends on stage of disease, the age of the patient, the patient's overall health, any signs or symptoms related to the lymphoma, and the location of the disease.
Treatment Options for Gastric MALT
For gastric MALT lymphoma, the initial treatment is antibiotic therapy to get rid of helicobacter pylori, which is typically given for two weeks. Approximately 70 percent to 90 percent of patients respond to antibiotic therapy, and approximately half of the patients require no further treatment. If the lymphoma relapses after antibiotic therapy, there are many additional treatment options available, including (in alphabetical order):
- Radiation (low dose)
- Surgical excision
Treatment Options for Non-gastric MALT
Non-gastric MALT can appear in a variety of areas throughout the body. Therefore, treatment is usually based on the exact location and extent of spread. Treatment typically includes surgery for certain sites (lung, breast) or radiation therapy with or without chemotherapy. More advanced disease usually includes immunoradiotherapy with chemotherapy. Among the common first-line treatments are bendamustine plus rituximab and R-CHOP (rituximab, cyclophosphamide, doxorubicin vincristine, prednisone). Recently, antibiotic therapy such as doxycycline has been shown to be effective in marginal zone lymphoma that affects the area around the eye ("ocular adnexal marginal zone lymphoma").
Treatment Options for Nodal Marginal Zone Lymphoma
Because nodal marginal zone lymphoma is most often a slow-growing disease, doctors may defer treatment until symptoms appear, an approach called "watch and wait" or "watchful waiting." When treatment is necessary, options include radiation therapy, chemotherapy, and other treatments commonly used in other types of slow-growing lymphomas, such as follicular lymphoma.
Treatment Options for Splenic Marginal Zone Lymphoma
Several treatment options exist for splenic marginal zone lymphoma. Some patients receive a splenectomy (surgical removal of the spleen) or, for those patients who are not surgical candidates, low-dose radiation of the spleen. Other patients may receive rituximab, a monoclonal antibody, with or without chemotherapy.
Treatments Under Investigation
Several new drugs and drug combinations are being studied in clinical trials for marginal zone lymphoma and other slow-growing lymphomas, including:
- B-cell receptor signaling blockers
- Ibritumomab tiuxetan
- Radaszkiewicz T, Dragosics B, Bauer P (1992).Gastrointestinal malignant lymphomas of the mucosa-associated lymphoid tissue: factors relevant to prognosis.Gastroenterology 102:1628
- Lymphoma research foundation