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Non-Hodgkin lymphoma

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Extranodal marginal zone of mucosa-associated lymphoid tissue (MALT lymphoma)

Marginal zone lymphomas are B-cell lymphomas. They are not very common and account for a small percentage of non-Hodgkin lymphomas (NHLs). There are 3 main types of marginal zone lymphomas:

Extranodal marginal zone lymphomas start in tissues or organs outside of the lymph nodes (extranodal). MALT lymphoma develops in mucosa-associated lymphoid tissue, in the mucosa or tissue that lines body organs or body cavities including:

  • gastrointestinalgastrointestinalReferring to or having to do with the digestive organs, particularly the stomach, small intestine and large intestine. (GI) tract
    • The stomach is the most common location for MALT lymphoma, but they can also occur in the small bowel and colon.
  • lungs
  • eyes, including the orbit (bony cavity that the eyeball sits in)
  • skin
  • salivary glands
  • thyroid gland
  • breasts

MALT lymphomas are the third most common type of NHL and account for about 8% of all cases of NHL. Most MALT lymphomas occur in people in their 60s.

Many people are diagnosed with localized or early stage disease that has not spread elsewhere in the body. MALT lymphomas are usually slow growing (indolent), but some can be high grade. They often remain in the area in which they started for a long period of time. Rarely, MALT lymphomas can change (transform) into a more aggressive large cell lymphoma.

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Risks

Many people with MALT lymphoma of the stomach (gastric lymphoma) have a history of a bacterial infection caused by Helicobacter pylori (H. pylori). H. pylori weaken the protective mucous coating of the stomach and can cause inflammation of the stomach (gastritis) and stomach ulcers. Not every one that has an H. pylori infection will develop a MALT lymphoma. About 5–10% of people with gastric MALT lymphoma do not have an H. pylori infection (H. pylori negative).

Other MALT lymphomas have been linked to bacterial or viral infections. People with MALT lymphomas in areas of the body other than the stomach often have a history of autoimmuneautoimmuneA disorder in which the immune system attacks healthy tissues in the body. diseases, such as:

  • Hashimoto’s thyroiditis – a disease that leads to a chronic inflammation of the thyroid gland and lowered thyroid function or hypothyroidism
  • Sjogren’s syndrome – a disease in which the body’s immune system mistakenly attacks its own moisture-producing glands, including the sweat, tear and salivary glands

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Treatment

MALT lymphomas are usually slow growing (indolent) and often respond well to treatment. Treatment is tailored to the stage, grade and location of the MALT lymphoma.

Early stage MALT lymphomas that occur in areas other than the stomach may be given local treatments, such as surgery or radiation therapy.

  • Surgery may be an option depending on the location in the body or how extensive the MALT lymphoma is.
  • Low doses of external beam radiation therapy may also be an option.

More advanced MALT lymphomas (stage III or IV) are usually treated the same as follicular lymphoma.

Treatment of MALT lymphomas of the stomach are discussed below.

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MALT lymphoma of the stomach

MALT lymphomas of the stomach (gastric MALT lymphomas) are staged and treated differently than MALT lymphomas that occur in other parts of the body. People with gastric lymphomas often have early stage disease when their lymphoma is first diagnosed.

Staging MALT lymphoma of the stomach

Healthcare professionals disagree about the best way to stage gastric MALT lymphoma. The 2 systems used are the Ann Arbor staging system and the TNM staging system.

Ann Arbor

The Ann Arbor staging system has been modified for gastric lymphomas.

StageDescription

I

Tumour is confined to the stomach without spread to the lymph nodes.

II

Tumour extends into the abdomen and has spread to the lymph nodes.

II1 – Cancer has spread to local lymph nodes (such as paragastric nodes).

II2 – Cancer has spread to distant lymph nodes (such as para-aortic, pelvic or inguinal nodes).

IIE

Tumour penetrates the serosa to spread to nearby (adjacent) organs or tissues.

IV

Widespread (disseminated) spread to extranodalextranodalOf or affecting an area or organ outside the lymph nodes. sites or spread to the lymph nodes above the diaphragm (supradiaphragmatic nodal involvement).

TNM

The TNM staging system for stomach cancer has also been applied to gastric MALT lymphoma. TNM stands for tumour, nodes, metastasis.

The depth that the primary tumour (T) in gastric MALT lymphoma has gone into the layers of the stomach corresponds to the T stage of stomach cancer.

T1

The lymphoma is confined to the mucosa or submucosa.

T1m – Lymphoma confined to the mucosa.

T1sm – Lymphoma confined to the submucosa.

T2

Lymphoma invades the muscularis (muscularis propria).

T3

Lymphoma penetrates the subserosa.

T4

Lymphoma has grown through the serosa or invades organs near the stomach.

N is the number and location of any regional lymph nodes that contain cancer cells.

N0

No cancer in regional lymph nodes.

N1–3

There is cancer in the regional lymph nodes.

M stands for distant metastasis and shows whether the cancer has spread to a different part of the body.

M0

No distant metastasis.

M1

Distant metastasis.

Note: M is not generally used in staging gastric MALT lymphoma.

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Treatment of MALT lymphoma of the stomach

Treatment options for gastric MALT lymphoma depend on its stage – whether it is localized or more advanced – and how the person responds to initial therapy.

Treatment of early stage MALT lymphoma of the stomach

Treatment options for early stage (localizedlocalizedConfined or restricted to the original (primary) site with no evidence of spread.) gastric MALT lymphoma that is confined to the stomach often include:

  • antibiotic therapy
    • Amoxicillin (Novamoxin) and other antibiotics are often the first treatment used for H. pylori infection in people with gastric lymphoma. They can be very effective in getting rid of H. pylori and causing the gastric lymphoma to go into remissionremissionA decrease in or the disappearance of signs and symptoms of a disease (such as cancer).. A combination of 2 or 3 antibiotics may be used.
    • Antibiotics may be given with drugs that lower the production of acid in the stomach, called proton pump inhibitors (PPI). These drugs may include omeprazole (Losec) or H2-receptor antagonists like ranitidine (Zantac).
    • Antibiotics are usually given for 10–14 days. This treatment is often very effective at shrinking the lymphoma. However, it can sometimes take several months for the treatment to be effective and doctors may need to give the drugs again.
    • After treatment with antibiotics, the inside of the stomach is often examined using a thin, lighted tube called a gastroscope (gastroscopy). A gastroscopy is repeated at certain times and biopsies are taken to see if the H. pylori are gone, if the lymphoma has shrunk or if the lymphoma has not recurred. This is an important part of follow-up after treatment with antibiotic therapy.
  • radiation therapy
    • External beam radiation therapy may be used if antibiotics don’t shrink the lymphoma or if the person is H. pylori negative.
  • surgery
    • Surgery for gastric MALT lymphomas is not used as much as it was in the past. Surgery to remove part or all of the stomach (partial or total gastrectomy) is sometimes done if the lymphoma remains after antibiotic therapy or if the gastric lymphoma progresses.
  • chemotherapy
    • Chemotherapy is sometimes used if the lymphoma does not respond to antibiotic therapy. Drugs that may be used include single drugs like chlorambucil (Leukeran), cyclophosphamide (Cytoxan, Procytox) or combinations like CHOP – cyclophosphamide, doxorubicin (Adriamycin), vincristine and prednisone.
  • biological therapy
    • Monoclonal antibodies are a type of biological therapy that is effective in treating certain types of NHL. Rituximab (Rituxan) may be another option if antibiotics do not reduce the lymphoma.

Treatment of advanced stage MALT lymphoma of the stomach

More advanced gastric MALT lymphomas are often treated like follicular lymphoma.

  • watchful waiting
    • People with gastric MALT lymphoma that is not progressing may be observed without being treated right away.
  • radiation therapy
    • External beam radiation therapy may be used if the lymphoma is large, is causing symptoms or is growing.
  • chemotherapy
    • Chemotherapy may be used instead of radiation therapy if the lymphoma is large, growing, widespread or comes back after being treated.
    • Chemotherapy drugs used are the same as those used for follicular lymphoma. These can include single drugs like chlorambucil (Leukeran), cyclophosphamide (Cytoxan, Procytox), fludarabine (Fludara) or cladribine (2-CDA, Leustatin).
    • Chemotherapy can also include combinations of chemotherapy drugs, such as:
      • CVP – cyclophosphamide, vincristine (Oncovin) and prednisone (Deltasone)
      • CHOP – cyclophosphamide, doxorubicin (Adriamycin), vincristine and prednisone
  • biological therapy
    • Rituximab (Rituxan) is another option if the gastric lymphoma is resistant to antibiotics, if the lymphoma is not associated with H. pylori infection, or if the lymphoma has relapsed.

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For more detailed information on specific drugs, go to sources of drug information.

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