Introduction

It may surprise you to learn that a common stomach infection might raise your chance of developing cancer. In some individuals, a persistent Helicobacter pylori infection can lead to a rare form of cancer known as MALT lymphoma. Fortunately, there are now more therapy choices to treat MALT lymphoma due to scientific improvements that have created more treatment options.¹ 

Monoclonal antibodies are one major category of these treatments that work by binding to specific proteins on cancer cells and boosting your immune system’s ability to destroy them. Antibiotics may be used to treat early cases, but more advanced types require specific treatments. One of them is rituximab, a lab-made antibody that helps your body find and get rid of the cancerous B cells in MALT lymphoma.¹

This article will help you understand:

• What MALT lymphoma is
• How monoclonal antibody treatments (such as rituximab) work to target cancer
• Some side effects you might experience with rituximab
• What to expect during treatment

Whether you or a loved one is facing MALT lymphoma or you’re just looking to learn more about this condition and its treatments, this article will guide you through everything you need to know.

What is MALT lymphoma?

Mucosa-associated lymphoid tissue (MALT) lymphoma is a type of non-Hodgkin lymphoma. It specifically originates from B cells, which are a type of white blood cell that normally help the body fight against infections. Unlike many other non-Hodgkin lymphomas that begin in the lymph nodes, MALT lymphoma usually develops in mucosal tissue, which lines various organs and sites throughout the body. As a result, there are different types of MALT lymphoma, as it can develop anywhere in the body.^1,2

When B cells in these tissues begin to grow and multiply uncontrollably, which is often triggered by chronic infections or inflammation, MALT lymphoma develops. This can cause long-term immune stimulation, which over time leads to changes in the B cells and eventually results in cancer.^1,2

Types of MALT lymphoma and where they develop

• Gastric MALT lymphoma:^1,3
  • This is the most common type and develops in the stomach lining. An infection with the Helicobacter pylori bacteria is typically associated with this type of MALT lymphoma
• Non-Gastric MALT lymphoma:^1,3
  • Lungs 
  • Thyroid glands 
  • Salivary glands
  • Eye area tissue (ocular adnexal MALT lymphoma) 

Risk factors

• Chronic infections:^3,4
  • Helicobacter pylori infection is the main cause of gastric MALT lymphoma
  • Chlamydia psittaci infection is associated with ocular adnexal MALT lymphoma in certain geographical regions, such as Germany
• Autoimmune diseases:³
  • The risk of developing MALT lymphoma is significantly higher in individuals with Sjögren's syndrome and Hashimoto's thyroiditis
• Older age - Most cases are found in people over 60, but it can happen at any age

Symptoms

Symptoms can vary based on where the lymphoma develops. For gastric MALT lymphoma, common symptoms include:¹

• Indigestion
• Nausea or vomiting
• Weight loss

Symptoms of non-gastric MALT lymphoma are related to the affected area, such as dry mouth and swelling in salivary glands, or eye irritation and blurred vision in ocular adnexal MALT lymphoma.¹

Most common treatments 

Treatment varies depending on the site and stage of lymphoma. Options can include:^1,2,5

• Antibiotic therapy - preferred first treatment for gastric MALT lymphoma caused by H.pylori infection
• Radiotherapy - treats localised and early-stage cases, particularly gastric MALT lymphoma
• Monoclonal antibody treatments, such as rituximab, treat lymphoma more precisely
• Chemotherapy combined with rituximab (chemoimmunotherapy) - treats more advanced cases of lymphoma, or if the lymphoma is unresponsive to other treatments

What are monoclonal antibodies?

Antibodies are proteins that are naturally made by your immune system to recognise and destroy harmful invaders called pathogens – these are bacteria, viruses, or other tiny organisms that can cause disease. You can think of antibodies as address labels – each antibody is designed to attach to a specific pathogen, marking it so the immune system knows exactly where to send its attack.⁶

Monoclonal antibodies, on the other hand, are lab-made versions of a single natural antibody. Imagine printing thousands of identical address labels from one original label. Because they are cloned from a single immune cell, monoclonal antibodies are identical and made to bind to the same target cells.⁶

How do monoclonal antibody treatments work?

Monoclonal antibodies have transformed cancer treatment by offering a more targeted approach. They work by recognising and binding to specific targets, typically a protein, on the surface of cancer cells. Different monoclonal antibodies have different jobs. Depending on the type, they might:⁶

• Act like address labels - marking cancer cells so the immune system knows which cells to destroy
• Stop cancer cells from receiving the signals they need to grow and divide
• Transport cell-killing substances straight to cancer cells without harming healthy cells 
• Strengthen your body’s ability to fight the cancer naturally

In the case of MALT lymphoma, monoclonal antibodies are designed to target B cells. This targeted approach helps reduce damage to healthy cells, leading to fewer side effects compared to traditional chemotherapy.^1,2,7

Meet rituximab

Rituximab is a medication used to treat certain B-cell cancers, such as MALT lymphoma. It belongs to monoclonal antibodies.⁸

How does rituximab work?

Rituximab targets a protein called CD20 that is found on the surface of B cells. When rituximab attaches to CD20, it essentially marks these cancer B-cells for your body’s natural defence system to attack and eliminate. This targeted process decreases the number of B cells in your body. The effect can last for several months since your body needs time to produce new B cells, which is why rituximab has proven effective against this type of lymphoma. Moreover, rituximab focuses on B cells only, which means it can eliminate the cancerous B-cells while leaving most of your other healthy cells unharmed.⁸

How is rituximab administered?

Rituximab can be used in different ways depending on how advanced the cancer is or whether other treatments (like antibiotics and chemotherapy) are being used alongside it. It’s often combined with other drugs, but in some cases, it can be used on its own.

Rituximab is usually given as an intravenous (IV) infusion. At first, patients get one treatment administered once a week for four weeks, then one treatment a month for another four months to keep it working. Your first treatment may take around 5 hours. But it may take longer if you experience an infusion-related reaction or other symptoms. People can also receive their treatment with a quick injection under the skin instead of sitting through a lengthy IV session - it's just as effective, and it is easier on the body.⁹

Does rituximab work well?

For those whose lymphoma is localised and linked to a Helicobacter pylori infection, antibiotics alone can sometimes make the cancer go away completely. For advanced cases when antibiotics are not enough, doctors have started using rituximab, which has shown great promise when used alone or in combination with chemotherapy.^5,10

Side effects of rituximab

While 540,000 patients worldwide have now received rituximab and the vast majority of patients have found it to be safe, side effects can include:^7,8

• Mild infusion-related reactions
• Increased risk of infections due to reduced B cell numbers
• When used in combination with chemotherapy, rituximab can increase the rate of neutropenia
• Rare side effects - including severe infections, such as progressive multifocal leukoencephalopathy (brain infection) from a weakened immune system

Your doctor will discuss these risks and monitor you through the treatment to keep you safe. Most side effects are manageable, but it is important to report any new symptoms to your doctor during treatment.

Where are we heading with monoclonal antibody treatment?

While rituximab works well for many people, scientists are exploring ways to combine it with more powerful treatments to improve results, especially for those whose lymphoma does not respond to initial treatment or returns.⁷

Newer therapies to treat gastric MALT lymphoma are being developed. They use specific antibodies to stop the growth of blood vessels - essentially “starving” the cancer by cutting off its "food supply" - by targeting the arteries that feed tumours.⁵

Overall, the success of rituximab has opened the door to even more advanced therapies for B-cell lymphomas like MALT lymphoma, offering hope for treatments that are not only more effective but also safer and more tailored to each person’s needs.

FAQs

How do you get a Helicobacter pylori infection? 

It usually develops in childhood and spreads from person to person through direct contact with saliva, vomit, and even contaminated food or surfaces.

Does rituximab cause hair loss like chemotherapy? 

You won’t usually experience hair loss with rituximab alone, unlike some chemotherapy treatments. This means your hair is often not affected if you are only being treated with rituximab. 

Is rituximab safe for older patients? 

If you’re older, rituximab can be a safe and effective treatment for you. Your healthcare team will closely monitor you to make sure any risks, like infections or other health concerns, are carefully managed during your treatment.

Summary

MALT lymphoma is a type of non-Hodgkin lymphoma that develops from B cells in mucosal tissues like the stomach. Monoclonal antibody treatments, such as rituximab, have made a big difference by specifically targeting cancerous B cells while helping limit damage to the rest of the body. 

While rituximab is generally effective, research continues to find even better ways to treat people living with this condition. If you or someone you care about has been diagnosed with MALT lymphoma, talking to your healthcare team about treatment options can help you make the right choices for your health.