The role of abdominal CT scan as follow-up after complete remission with successful Helicobacter pylori eradication in patients with H. pylori-positive stage I(E1) gastric MALT lymphoma

[Diagnosis and Treatment of Gastric Mucosa-associated Lymphoid Tissue Lymphoma]

The stomach is the most common primary site of an extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT) type, which is characterized by an indolent clinical course. A diagnosis of gastric MALT lymphoma requires an endoscopic biopsy that should be confirmed by an experienced pathologist. Gastric MALT lymphoma shows a variable endoscopic appearance, including erosion, erythema, discoloration, atrophy, ulcer, and subepithelial lesion. The distribution is often multifocal. Therefore, clinical suspicion and multiple biopsies are essential for an accurate diagnosis. Gastric MALT lymphoma is almost invariably associated with a Helicobacter pylori (H. pylori) infection. H. pylori eradication therapy is the mainstay of treatment, which must be delivered to all patients regardless of the H. pylori infection status or stage. For patients who have failed to achieve remission following eradication therapy, radiotherapy or chemotherapy can be considered. Radiotherapy is an effective treatment modality for a localized stage and shows excellent outcomes. In the presence of disseminated or advanced disease, chemotherapy and/or immunotherapy with the anti-CD20 monoclonal antibody, rituximab, can be applied. Treatment should be individualized according to the stage and symptoms, as well as the patients' preference. Given that the clinical course of gastric MALT lymphoma is usually indolent, watchful waiting may be an adequate strategy in selected cases where scheduled follow-up is guaranteed.

The Role of Endoscopic Ultrasound in the Diagnosis and Management of Primary Gastric Lymphoma

Endoscopic ultrasound (EUS) is considered a valuable diagnostic tool during the workup of malignant gastric lesions, including primary gastric lymphomas (PGL). Although endoscopy combined with multiple biopsies remains essential in the establishment of PGL diagnosis, EUS utilization in locoregional disease staging has been well documented in the literature. Data also support the possible role of EUS in prediction of response to first-line treatment, that is, Helicobacter pylori eradication. However, its application in the posttreatment setting remains problematic, since concordance rates between endosonography and histology findings during follow-up seem to vary substantially. The aim of the present review is to summarize all available data regarding the role of EUS in the management of PGL.

Meta-analysis of first-line triple therapy for helicobacter pylori eradication in Korea: is it time to change?

Proton pump inhibitor (PPI)-based triple therapy consisting of PPI, amoxicillin, and clarithromycin, is the recommended first-line treatment for Helicobacter pylori infection. However, the eradication rate of triple therapy has declined over the past few decades. We analyzed the eradication rate and adverse events of triple therapy to evaluate current practices in Korea. A comprehensive literature search was performed up to August 2013 of 104 relevant studies comprising 42,124 patients. The overall eradication rate was 74.6% (95% confidence interval [CI], 72.1%-77.2%) by intention-to-treat analysis and 82.0% (95% CI, 80.8%-83.2%) by per-protocol analysis. The eradication rate decreased significantly from 1998 to 2013 (P < 0.001 for both intention-to-treat and per-protocol analyses). Adverse events were reported in 41 studies with 8,018 subjects with an overall incidence rate of 20.4% (95% CI, 19.6%-21.3%). The available data suggest that the effectiveness of standard triple therapy for H. pylori eradication has decreased to an unacceptable level. A novel therapeutic strategy is warranted to improve the effectiveness of first-line treatment for H. pylori infection in Korea.

Role of Helicobacter pylori in gastric mucosa-associated lymphoid tissue lymphomas

Mucosa-associated lymphoid tissue (MALT) lymphoma is an indolent extranodal marginal zone B-cell lymphoma, originating in acquired MALT that is induced in mucosal barriers as part of a normal adaptive immune response to a chronic immunoinflammatory stimulus, most notably chronic infection by Helicobacter pylori (H. pylori). This antigenic stimulation initially leads to lymphoid hyperplasia; the acquisition of additional genetic aberrations culminates in the activation of intracellular survival pathways, with disease progression due to proliferation and resistance to apoptosis, and the emergence of a malignant clone. There are descriptions of MALT lymphomas affecting practically every organ and system, with a marked geographic variability partially attributable to the epidemiology of the underlying risk factors; nevertheless, the digestive system (and predominantly the stomach) is the most frequently involved location, reflecting the gastrointestinal tract’s unique characteristics of contact with foreign antigens, high mucosal permeability, large extension and intrinsic lymphoid system. While early-stage gastric MALT lymphoma can frequently regress after the therapeutic reversal of the chronic immune stimulus through antibiotic eradication of H. pylori infection, the presence of immortalizing genetic abnormalities, of advanced disease or of eradication-refractoriness requires a more aggressive approach which is, presently, not consensual. The fact that MALT lymphomas are rare neoplasms, with a worldwide incidence of 1-1.5 cases per 10⁵ population, per year, limits the ease of accrual of representative series of patients for robust clinical trials that could sustain informed evidence-based therapeutic decisions to optimize the quality of patient care.

Review article: common misconceptions in the management of Helicobacter pylori-associated gastric MALT-lymphoma

BACKGROUND

Helicobacter pylori infection is the main cause of gastric mucosa-associated lymphoid tissue (MALT) lymphoma.

AIM

To review several common misconceptions in the management of H. pylori-associated gastric MALT-lymphoma.

METHODS

Bibliographical searches were performed in MEDLINE up to June 2011.

RESULTS

If adequate diagnostic methods are used, and if only low-grade lymphomas are considered, the prevalence of H. pylori infection is very high (almost 90%). H. pylori eradication is effective in treating approximately 80% of patients with early stage lymphoma. In H. pylori-positive gastric high-grade lymphomas, antibiotic therapy should always be prescribed, as approximately 50% of them regress after H. pylori eradication. Patients with early stage MALT lymphoma negative for H. pylori might still benefit from antibiotic treatment as the sole treatment. Complete remission of gastric MALT lymphoma after H. pylori eradication can take even >12 months. PCR assay for the detection of monoclonal B cells remains positive in many cases after complete remission has been reached. Patients with a persistent clonal band should not be treated unless the lymphoma can be histologically demonstrated. Synchronous occurrence of gastric adenocarcinoma and MALT lymphoma has been repeatedly reported. In some patients in complete remission, eradication of H. pylori does not prevent later development of early gastric cancer. Gastric lymphoma recurrence occurs in some patients after both bacterial and lymphoma regression. H. pylori reinfection does not constitute a prerequisite for lymphoma recurrence.

CONCLUSIONS

The present article states several misconceptions in the management of H. pylori-associated gastric MALT-lymphoma in clinical practice, reviews the related scientific evidence and proposes the adequate attitude in each case.