What is the treatment approach for gastric MALT (Mucosa-Associated Lymphoid Tissue) lymphoma?

Treatment of Gastric MALT Lymphoma

The first-line treatment for gastric MALT lymphoma should be Helicobacter pylori eradication therapy, regardless of stage, as this can induce lymphoma regression and provide long-term disease control in most patients. 1, 2

Initial Diagnostic Workup

• Diagnosis is based on histopathologic evaluation of gastric biopsies, which should include multiple samples from each region of the stomach, duodenum, gastroesophageal junction, and any abnormal-appearing sites 1
• H. pylori status must be determined through histochemistry, urea breath test, stool antigen test, or serology 1
• Fluorescence in situ hybridization (FISH) or PCR for detection of t(11;18) translocation is useful for identifying patients unlikely to respond to antibiotic therapy 1
• Complete staging should include:
  • Endoscopic ultrasound to evaluate regional lymph nodes and gastric wall infiltration 1
  • Complete blood counts and basic biochemical studies including LDH and β2-microglobulin 1
  • CT scan of chest, abdomen, and pelvis 1
  • Bone marrow aspirate and biopsy 1

Treatment Algorithm Based on H. pylori Status

H. pylori-Positive Patients

• First-line treatment: H. pylori eradication therapy using proton-pump inhibitor (PPI) plus clarithromycin-based triple therapy with either amoxicillin or metronidazole for 10-14 days 1, 2
• Confirm eradication with urea breath test or stool antigen test at least 6 weeks after therapy and 2 weeks after PPI withdrawal 1, 2
• If initial eradication fails, attempt second-line therapy with alternative triple- or quadruple-therapy regimens of PPI plus antibiotics 1
• Wait at least 12 months before starting another treatment in patients who achieve clinical and endoscopic remission, even if persistent lymphoma is present at histological level 1, 2

H. pylori-Negative Patients

• A trial of antibiotic therapy may still be worthwhile as occasional lymphoma responses have been reported (possibly due to false-negative tests or infection by other Helicobacter species) 1, 3
• If no signs of lymphoma regression are seen at repeat endoscopy 2-3 months after antibiotics, proceed with oncological treatment 1

Treatment for Refractory or H. pylori-Negative Disease

• For localized disease (stage I-II), moderate-dose involved-field radiotherapy (24-30 Gy to the stomach and perigastric nodes over 3-4 weeks) is the preferred option 1, 4
• For systemic disease (stage IV), consider:
  • Systemic chemotherapy with oral alkylating agents (cyclophosphamide or chlorambucil) or purine nucleoside analogs (fludarabine, cladribine) 1, 2
  • Immunotherapy with rituximab, which has shown activity in phase II studies 1, 2
  • Combined chemoimmunotherapy, particularly rituximab plus chlorambucil, which has proven efficacy in randomized studies 2
• Patients with histological transformation to diffuse large cell lymphoma should be treated according to diffuse large cell lymphoma protocols 1

Follow-up Recommendations

• Endoscopic follow-up with multiple biopsies 2-3 months after treatment to document H. pylori eradication 1, 2
• Subsequent endoscopy with biopsies at least twice per year for 2 years to monitor histological regression 1, 2
• For persistent but stable residual disease, a wait-and-see policy may be safe with continued endoscopic surveillance 1
• Long-term follow-up with annual blood counts and appropriate radiological or ultrasound examinations 1

Special Considerations

• Patients with t(11;18) translocation are less likely to respond to antibiotics alone and may be unresponsive to alkylating agents as sole treatment 2
• Surgery is generally not recommended as it has not shown superior results compared to more conservative approaches 1
• Even in H. pylori-negative cases, a significant percentage of patients may benefit from antibiotic therapy with durable remissions, suggesting a trial of antibiotics before proceeding to more aggressive treatments 3