Helicobacter pylori infection is known to play an important part in the development and progression of MALT (mucosa-associated lymphoid tissue)-type gastric lymphoma, and eradication of H. pylori is well established as an initial treatment for MALT lymphoma that is confined to the gastric wall.
In cases where progression of the disease, or of lymphoma infiltrates, continues 12 months after eradication of H. pylori, patients are usually referred for surgery or radiotherapy.
In a research letter to the latest edition of The Lancet, Professor Wolfgang Fischbach and colleagues from the University of Würzburg, in Würzburg, Germany, describe their experiences with 7 patients who declined further treatment.
The research group investigated 5 male and 2 female patients, aged 43 to 69 years, who were diagnosed with low-grade gastric MALT-type lymphoma (extranodal marginal zone B-cell lymphoma, according to the revised European American lymphoma (REAL) and WHO classifications) by review of centralized histological records.
H pylori infection was shown histologically and by the rapid urease test.
Complete diagnostic work-up, which included abdominal and cervical ultrasound, thoracic and abdominal CT, bone marrow puncture, and endoscopic gastric ultrasound, showed stage I lymphoma (according to the Ann Arbor staging system) in all patients.
Patients received triple therapy with omeprazole, clarithromycin, and metronidazole or amoxycillin, and were followed up with endoscopy and gastric biopsy every 3 months.
Endoscopy showed that the initial macroscopic lesions had returned to normal or revealed features of post H pylori gastritis only.
All patients became negative for H. pylori by the rapid urease test, and on repeat biopsies.
However, lymphoma regression was not achieved within 12 months after successful eradication of the bacterium, as shown by histological and immunohistochemical examination.
| Potential strategies for gastric MALT lymphoma - could be broader than previously thought |
The researchers took biopsy samples by use of a mapping protocol (antrum, 4 biopsies; corpus, 4; fundus, 2; and any visible lesion, 8 to 10).
Clonality and presence of t(11;18) translocations were then determined by standard immunoglobulin-gene-rearrangement-PCR and PCR for API2-MALT1 chimeric transcripts.
The researchers found there to be no signs of lymphoma progression or high-grade transformation within a median observation time of 34 months (range 20-44 months).
A total of 4 out of 5 patients tested were positive for t(11;18) at initial diagnosis.
One of these patients became negative for t(11;18) 20 months after eradication therapy, whereas the other 3 remained positive during follow-up.
Commenting on their findings, the researchers say that they saw no cases of lymphoma progression or high-grade transformation within an observation period of almost 3 years.
They add that the potential strategies for management of patients with gastric MALT lymphoma might, therefore, be broader than previously thought, and could include a watch-and-wait strategy.
Continuing, they say that the finding that more cases were t(11;18) positive than were negative is in accord with those of recent reports on MALT lymphoma after H. pylori eradication, but that since patients who are negative for t(11;18) show many more clonal aberrations than those who are positive, as shown by microsatellite analysis, such patients may need more intensive follow-up.
The research group end by cautioning that they investigated only a few cases and so this strategy should be tested in a larger series of patients with long-term follow-up, including detailed molecular analyses.
Also, patients managed by a watch-and-wait strategy should be compared with those receiving standard oncological treatment.
"We believe that to postpone oncological treatment is justifiable in patients with minimal residual stage I low-grade gastric MALT lymphoma, after successful eradication of H. pylori. Very thorough investigations are, however, mandatory when deciding to do so."