Understanding Marginal Zone Lymphoma
Marginal zone lymphoma (MZL) is a slow-growing type of non-Hodgkin lymphoma (NHL), or blood cancer.
Lymphocytes, a type of white blood cell in the immune system, has two types that can grow uncontrollably and become cancerous: B lymphocytes (B cells) and T lymphocytes (T cells). Marginal zone lymphoma is a slow-growing, B-cell cancer that can spread throughout the lymph nodes, spleen, bone marrow, blood and other organs. Sometimes the cells form a mass called a tumor.1
There are three subtypes of MZL: extranodal, nodal, and splenic.2
MZL accounts for about 8% of all non-Hodgkin type cancers diagnosed and is slightly more common in women than men.
How does marginal zone lymphoma develop?
The most common form of MZL is extranodal or mucosa-associated lymphoid tissue (MALT) and occurs in about two-thirds of all MZL cases. It is found outside the lymph nodes, most often in the stomach, though sometimes in the breast, small intestine, salivary gland, thyroid, around the eyes, and lungs.
MALT lymphoma comes in two forms:
- Gastric, so named because it most often develops in the stomach
- Non-gastric, which develops outside the stomach
Many times, MALT is preceded by a medical history of chronic infection, inflammation, or autoimmune disorders affecting the organ where the cancer is found. For example, Helicobacter pylori (h. pylori), a bacteria known to cause stomach ulcers, is often found in patients with gastric MALT lymphoma.1
Nodal MZL is found in the lymph nodes and accounts for about a third of all MZL cases.1
Splenic MZL is usually found in the spleen, blood, and bone marrow, often in people who also have hepatitis C virus (HCV) infection. It occurs in about 8% of all MZL cases.1
Risk factors for marginal zone lymphoma
Risk factors for developing MZL are:
- Having Sjögren syndrome, lupus, or any other autoimmune condition that activates B-cells
- Hepatitis C infection
- Having a peptic ulcer
- Having asthma
- A first-degree relative (parent, sibling, child) with any leukemia or lymphoma
- Hair–dye use
- Occupations such as general carpenter, general laborer, painter, and metalworker2
Symptoms for marginal zone lymphoma
Not everyone with MZL experiences symptoms, but for those who do, symptoms can be vague and include:
Other signs that point to MZL (particularly MALT) are gastric pain, nausea, an enlarged spleen, and signs of gastric bleeding such as anemia.4
Stages of MZL
Stages one and two are considered early stages.
- Stage 1: MZL is found in only one lymphatic area.
- Stage 2: MZL is found in two or more lymph nodes, above or below the diaphragm.
Stages three and four are considered advanced stages.
- Stage 3: MZL is found in several lymph nodes above and below the diaphragm.
- Stage 4: MZL has spread to multiple organs.
What is a common prognosis marginal zone lymphoma?
Survival rates vary depending on the type of MZL a person has, their age at diagnosis, where the cancer is located, and the presence of other health issues. One study found that five-year survival rates between 1995 and 2009 were:5
- MALT - 88.7%
- Splenic - 79.7%
- Nodal - 76.5%5
However, the American Society of Hematology published a study at roughly the same time and found slightly different results:
- MALT - 85%
- Splenic – 50-88%, depending on other risk factors
- Nodal – 60-70%4
Given that MZL is a slow-growing cancer, early detection and watchful monitoring can improve the chances of long-term survival. Many new drugs for MZL and other slow-growing lymphomas are being studied.1
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