MALT lymphomas are divided into two broad categories: gastric MALT lymphoma and non-gastric MALT lymphoma. This article will address the first of these, gastric MALT lymphoma, or lymphomas that affect the gastrointestinal (GI) tract.
Unlike all other known subtypes of non-Hodgkin's lymphoma, a cause of some gastric MALT lymphoma has in all probability been identified: a bacterial infection caused by a germ called Helicobacter Pylori, or H. pylori.
H. pylori causes problems by infecting the stomach lining as well as the duodenum. In addition to being the perceived cause of some cases of gastric MALT lymphoma, H. pylori has also been implicated in stomach ulcers and some non-lymphoma stomach cancers.
A diagnosis of gastric MALT lymphoma requires an endoscopic biopsy. Biopsy through fine needle aspiration (FNA) is not considered adequate.
Determining whether or not a person has been infected with the H. pylori bacterium can be accomplished through 1) a stool antigen test, 2) a blood test that seeks out an immune response (or antigen) to the bacterium, 3) a special breath test, 4) a biopsy.
It is not common for gastric MALT lymphoma to be diagnosed in later stages (III or IV). Instead, most cases are discovered in early-stage (I or II), and once discovered, doctors then must determine whether the cancer is H. pylori positive or H. pylori negative.
If the patient's cancer is H. pylori positive, then treating gastric MALT lymphoma becomes much different than treatment for other lymphomas: the patient is generally put on a schedule of antibiotics, and following that, evaluated by way of endoscopy to make certain that the bacterium is no longer present.
If the patient's cancer is H. pylori negative, treatment involves either radiotherapy, or the immunotherapy drug Rituxan. Following that, the patient undergoes an endoscopy for restaging.