Pulmonary MALT lymphoma is a rare and typically slow-growing cancer that affects B cells in the mucous lining of your lungs. It may not cause symptoms and has higher survival rates than other types of non-Hodgkin’s lymphoma.

Many of the organs in your body are lined with mucous membranes. These membranes play a role in your immune system, helping to fight off infections. This type of tissue is called mucosa-associated lymphoid tissue (MALT).

Your MALT is a part of your lymphatic system, which is part of your immune system. Like your other lymphatic organs, your MALT can develop cancer. When cancer affects your lymphatic system, it’s known as lymphoma. Cancer that affects your MALT is known as MALT lymphoma.

Pulmonary MALT lymphoma is cancer that affects the MALT in your lungs. It affects certain types of white blood cells, known as B cells. Though rare, pulmonary MALT lymphoma is the most common type of B-cell lymphoma that affects your lungs.

Keep reading to learn more about this type of MALT lymphoma, including causes, symptoms, and treatment options.

Talking about lymphoma

Doctors and other healthcare professionals use several different terms to refer to lymphoma. You may hear the following terms that also apply to pulmonary MALT lymphoma:

Non-Hodgkin’s lymphoma (NHL): About 11% of lymphomas feature a special kind of cell known as a Reed-Stenberg cell. Doctors call those cancers Hodgkin’s lymphomas. But most lymphomas, including pulmonary MALT lymphoma, are a type of NHL.

B-cell lymphoma: NHL can affect your B cells or T cells. Pulmonary MALT lymphomas belong to the 85% of NHL cases that are B-cell lymphomas.

Marginal zone lymphoma (MZL): The marginal zone is the space between your lymphoid and nonlymphoid tissue. MZL occurs when cancer affects your B cells in this space. MALT lymphomas are the most common type of MZL.

All cancer is due to changes (mutations) that occur in the DNA of your cells. Lymphoma results when these mutations affect your lymphocytes (B cells or T cells). The affected lymphocytes divide out of control and lose their ability to help fight infections.

In pulmonary MALT lymphoma, these mutations affect the B cells in the lymphoid tissue that lines your lungs. Scientists don’t exactly know what triggers these DNA changes.

According to a 2016 review, infections like Helicobacter pylori and Borrelia burgdorferi are known to cause MALT lymphoma in other areas of your body. A 2014 study of people with pulmonary MALT lymphoma found that they were more likely than healthy controls to test positive for a type of bacteria called Achromobacter xylosoxidans.

A similar 2018 study didn’t come to the same conclusion, suggesting that more research is needed.

It may also be due to chronic inflammation or recurring infections.

Pulmonary lymphomas are more common in older adults, with the median age to receive a diagnosis being 60 years old.

Certain autoimmune diseases may increase your risk of developing MALT lymphomas. These include:

How common is pulmonary MALT lymphoma?

Although pulmonary MALT lymphoma is the most common B-cell lymphoma to affect your lungs, it’s still quite rare. NHL that starts in your lungs accounts for only 0.5% of all lung cancers and 0.4% of all lymphomas.

MALT lymphoma in your lungs doesn’t always cause symptoms. Almost half of people with pulmonary MALT lymphoma don’t have any symptoms when they receive a diagnosis. In some cases, it may be an incidental finding a doctor discovers after running routine or diagnostic tests for another condition.

Possible symptoms of pulmonary MALT lymphoma may include:

Some of these symptoms are also common in other cancers of the lungs. It’s important to see a doctor for a proper diagnosis.

Like in other lymphomas, you may also experience “B symptoms.” These usually suggest that your cancer is more advanced and can include:

  • night sweats
  • fever
  • rapid weight loss

B symptoms may indicate a transformation of MALT lymphoma into a high-grade, large-cell version. Left untreated, high-grade lymphoma may grow and spread rapidly.

Research has consistently shown that 55% to 63% of people with pulmonary MALT lymphoma experience respiratory symptoms, while about 15% to 22% experience B symptoms.

To diagnose pulmonary MALT lymphoma, a doctor will first consider your individual risk factors for this cancer and any symptoms you may be experiencing.

They may then order diagnostic tests, such as:

Treatment for pulmonary MALT lymphoma depends on the stage of your cancer, as well as your age and overall health.

A doctor may recommend one or a combination of the following options:

  • Radiotherapy: Doctors can direct high-dose radiation at your lungs to kill cancer cells, especially in the early stages.
  • Surgery: Another option for early stages is surgically removing tumors from the lining of your lungs.
  • Targeted therapy: This treatment option targets cancerous cells without disrupting healthy ones.
  • Chemotherapy: These systemic drugs also kill cancerous cells. Doctors may use a combination of chemotherapy medications for people with more advanced MALT lymphoma.

Doctors may also consider a “wait-and-see” approach if your cancer is at a low stage and doesn’t cause symptoms.

Because pulmonary MALT lymphoma tends to stay in your lungs without spreading for a long time, you have a better outlook with it than you would with many other cancers. Pulmonary MALT lymphoma is curable in most people. But your exact outlook will depend on:

  • how early you receive a diagnosis
  • your cancer stage
  • presence of B symptoms
  • your age and overall health

According to 2019 research, pulmonary MALT lymphoma has a 5-year overall survival rate of 87.1%. That means about seven out of every eight people with the disease are still alive 5 years after receiving the diagnosis. The median survival is more than 10 years, meaning half of people with the disease live for 10 years or longer.

With advancements in detection and treatment, survival rates may improve still. The outlook people with for NHL as a whole has improved over recent years, with about a 2% decrease in deaths each year between 2011 and 2020.

Recurrence of pulmonary MALT lymphoma

Even after successful treatment, it’s important to follow up with a doctor regularly. They may wish to monitor you for several years, as almost half of pulmonary MALT lymphomas return within 2 years of surgery to remove the tumor.

Pulmonary MALT lymphoma is a type of cancer that begins in the B cells of the mucosal lining of your lungs. While not as common as gastric forms, people with this type of lymphoma typically have a positive outlook due to its slow growth rate.

Still, it’s important not to dismiss possible symptoms, such as chronic cough or chest pain. Not only could these symptoms be related to another condition, but it’s also possible for pulmonary MALT lymphoma in some people to become advanced without treatment.

Consider talking with a doctor if you’re experiencing chronic lung symptoms, are older than 60 years old, and have certain risk factors for this type of cancer, such as a history of chronic infections or autoimmune diseases. They can help you decide the appropriate next steps for you.