Eradication therapy in Helicobacter pylori-negative, gastric low-grade mucosa-associated lymphoid tissue lymphoma patients: a systematic review

[Gastrointestinal mucosa-associated lymphoma]

Mucosa-associated lymphomas of the gastrointestinal tract are a heterogeneous group differing in pathogenesis, localization and therapeutic options. For all of them, differentiated treatment requires an exact determination of lymphoma stage. For gastric MALT lymphoma, the pathogenetic role of Helicobacter pylori infection has become evident in the last 30 years. These insights were consequently implemented into clinical practice. Nowadays, Helicobacter pylori eradication is the treatment of choice for gastric MALT lymphoma, leading to complete remission of the lymphoma in the majority of cases. In the absence of success, radiotherapy is available in localized stages I/II E with excellent results. Immuno-chemotherapy is the domain for advanced stages III/IV E, and surgery plays no role any more. The rare intestinal and colorectal MALT lymphomas require an individualized therapeutic approach.

Should All Patients With Stage IE Gastric Mucosa-Associated Lymphoid Tissue Lymphoma Receive Antibiotic Eradication Therapy for Helicobacter pylori?

PURPOSE

H. pylori eradication therapy (HPE) can lead to tumor regression in H. pylori-positive (HPP) gastric mucosa-associated lymphoid tissue (MALT) lymphoma. However, some patients do not have detectable H. pylori (HP) infection (H. pylori-negative [HPN]) and the guidelines differ in their initial approach to HPN patients. The National Comprehensive Cancer Network (NCCN) recommends proceeding to radiation therapy, whereas European Society for Medical Oncology suggests HPE for every patient, even those who are HPN. To address this issue, we evaluated the effectiveness of HPE in limited-stage gastric MALT lymphoma.

MATERIALS AND METHODS

We retrospectively reviewed patients newly diagnosed with stage IE gastric MALT lymphoma between January 2002 and December 2022. The primary outcome was the complete remission (CR) rate defined as no macroscopic findings of lymphoma and negative gastric biopsy at the follow-up gastric endoscopy.

RESULTS

Fifty-two patients were reviewed, and HP infection was detected in 19 (36.5%) patients-14 by immunostaining, three by serology, and one each by stool antigen and urea breath test. All 19 HPP and eight of the 33 HPN patients received HPE treatment. The CR rate was 63% (12/19) in HPP patients and 13% (1/8) in HPN patients (P = .033). After a median follow-up of 89.7 months, only two of the 12 HPP patients achieving CR have relapsed; the one HPN patient who received HPE remains in CR at 12+ months.

CONCLUSION

For limited-stage HPP gastric MALT lymphoma, HPE is an effective and durable first-line treatment and should be used. For HPN patients, the CR rate with HPE is very low in our experience and is thus in support of the NCCN guideline.

H pylori-Negative MALT-Associated Extranodal Marginal Zone Lymphoma: A Comprehensive Case Report and Literature Review

Extranodal marginal zone B-cell lymphoma (ENMZL) of mucosa-associated lymphoid tissue (MALT), a rare subtype of B-cell lymphoma, is typically associated with Helicobacter pylori (H pylori) infection, especially in gastric cases. However, this article presents 2 unique cases of H pylori-negative colonic ENMZL, challenging the conventional understanding of the disease. The first case involves an 80-year-old male diagnosed with Stage 1E ENMZL in the descending colon, and the second describes a 74-year-old male with sigmoid colon ENMZL. Both cases lacked H pylori infection, adding complexity to their management. Accompanying these case studies is a comprehensive literature review, delving into the epidemiology, pathology, clinical features, diagnosis, and treatment of H pylori-negative ENMZL, with a focus on gastrointestinal involvement. This review highlights the importance of considering H pylori-negative cases in ENMZL diagnosis and management, illustrating the need for further research and individualized treatment approaches in this uncommon lymphoma subtype.

Helicobacter pylori-Negative Gastric Mucosa-Associated Lymphoid Tissue Lymphoma in a Girl

Introduction

Extranodal marginal zone lymphoma (MZL) arises in a number of epithelial tissues, including the stomach, salivary gland, lung, small bowel, thyroid, ocular adnexa, skin, and elsewhere. It has also been called low-grade B-cell lymphoma of mucosa-associated lymphoid tissue (MALT). MALT lymphoma predominantly occurs in adults and is rare in children.

Case Presentation

We report a case of MALT lymphoma involving the stomach, which is the most common subtype, in a 12-year-old girl. Initially, the patient relapsed after antibiotic therapy but achieved successful treatment subsequently through irradiation.

Conclusion

Helicobacter pylori eradication therapy should be given to all patients with gastric MZL, irrespective of stage. In patients who do not respond to antibiotic therapy, treatment options such as irradiation and systemic cancer therapies should be considered, depending on the disease stage.

Bacteria in cancer initiation, promotion and progression

Cancer cells originate from a series of acquired genetic mutations that can drive their uncontrolled cell proliferation and immune evasion. Environmental factors, including the microorganisms that colonize the human body, can shift the metabolism, growth pattern and function of neoplastic cells and shape the tumour microenvironment. Dysbiosis of the gut microbiome is now recognized as a hallmark of cancer by the scientific community. However, only a few microorganisms have been identified that directly initiate tumorigenesis or skew the immune system to generate a tumour-permissive milieu. Over the past two decades, research on the human microbiome and its functionalities within and across individuals has revealed microbiota-focused strategies for health and disease. Here, we review the evolving understanding of the mechanisms by which the microbiota acts in cancer initiation, promotion and progression. We explore the roles of bacteria in gastrointestinal tract malignancies and cancers of the lung, breast and prostate. Finally, we discuss the promises and limitations of targeting or harnessing bacteria in personalized cancer prevention, diagnostics and treatment.

Role of non-Helicobacter pylori gastric Helicobacters in helicobacter pylori-negative gastric mucosa-associated lymphoid tissue lymphoma

Marginal zone lymphomas rank as the third most prevalent form of non-Hodgkin B-cell lymphoma, trailing behind diffuse large B-cell lymphoma and follicular lymphoma. Gastric mucosa-associated lymphoid tissue lymphoma (GML) is a low-grade B-cell neoplasia frequently correlated with Helicobacter pylori (H. pylori)-induced chronic gastritis. On the other hand, a specific subset of individuals diagnosed with GML does not exhibit H. pylori infection. In contrast to its H. pylori-positive counterpart, it was previously believed that H. pylori-negative GML was less likely to respond to antimicrobial therapy. Despite this, surprisingly, in-creasing evidence supports that a considerable proportion of patients with H. pylori-negative GML show complete histopathological remission after bacterial eradication therapy. Nonetheless, the precise mechanisms underlying this treatment responsiveness are not yet fully comprehended. In recent years, there has been growing interest in investigating the role of non-H. pylori gastric helicobacters (NHPHs) in the pathogenesis of H. pylori-negative GML. However, additional research is required to establish the causal relationship between NHPHs and GML. In this minireview, we examined the current understanding and proposed prospects on the involvement of NHPHs in H. pylori-negative GML, as well as their potential response to bacterial eradication therapy.

Clinical Management of Patients with Gastric MALT Lymphoma: A Gastroenterologist's Point of View

Gastric mucosa-associated lymphoid tissue (MALT) lymphomas (GML) are non-Hodgkin lymphomas arising from the marginal zone of the lymphoid tissue of the stomach. They are usually induced by chronic infection with Helicobacter pylori (H. pylori); however, H. pylori-negative GML is of increasing incidence. The diagnosis of GML is based on histological examination of gastric biopsies, but the role of upper endoscopy is crucial since it is the first step in the diagnostic process and, with currently available novel endoscopic techniques, may even allow an in vivo diagnosis of GML per se. The treatment of GML, which is usually localized, always includes the eradication of H. pylori, which should be performed even in H. pylori-negative GML. In the case of GML persistence after eradication of the bacteria, low-dose radiotherapy may be proposed, while systemic treatments (immunochemotherapy) should be reserved for very rare disseminated cases. In GML patients, at diagnosis but even after complete remission, special attention must be paid to an increased risk of gastric adenocarcinoma, especially in the presence of associated gastric precancerous lesions (gastric atrophy and gastric intestinal metaplasia), which requires adequate endoscopic surveillance of these patients.

Long-term clinical outcomes of gastric mucosa-associated lymphoid tissue lymphoma in real-world experience

This long-term, retrospective, single-center study evaluated real-world clinical outcomes of gastric mucosa-associated lymphoid tissue (MALT) lymphoma using different therapeutic modalities and analyzed factors affecting survival outcomes and long-term prognosis. We enrolled 203 patients with pathologically confirmed low-grade gastric MALT lymphoma and examined their treatment responses. Helicobacter pylori eradication was performed in all patients with H. pylori infection (HPI) and localized stage gastric MALT lymphoma. All patients underwent pre-treatment and physical evaluations, with complete blood count, biochemistry panel, and staging workup. Among 144 HPI-positive patients with stage I or II1-2 disease who underwent H. pylori eradication, 112 (77.8%) achieved complete remission (CR). All HPI-negative patients who received first-line radiotherapy achieved CR (100%), but only 22 of 27 first-line chemotherapy-treated patients achieved CR (81.5%). Lesions in the proximal upper-third or in multiple locations and an invasion depth to the submucosa or deeper were associated with poor response to eradication, and HPI negativity was significantly correlated with poor progression-free survival. HPI eradication treatment should be the first-line treatment for patients with localized stage HPI-positive gastric MALT lymphoma. The "watch-and-wait" strategy should be adopted for delayed responders. We suggest radiotherapy for patients with a localized HPI-negative status or when eradication has failed.

Comprehensive Analysis of Gene Expression Profiling to Explore Predictive Markers for Eradication Therapy Efficacy against Helicobacter pylori-Negative Gastric MALT Lymphoma

Although radiotherapy is the standard treatment for Helicobacter pylori (Hp)-negative gastric mucosa-associated lymphoid tissue (MALT) lymphoma, eradication therapy using antibiotics and an acid secretion suppressor can sometimes induce complete remission. We explored predictive markers for the response to eradication therapy for gastric MALT lymphoma that were negative for both API2-MALT1 and Hp infection using comprehensive RNA sequence analysis. Among 164 gastric MALT lymphoma patients who underwent eradication therapy as primary treatment, 36 were negative for both the API2-MALT1 fusion gene and Hp infection. Based on eradication therapy efficacy, two groups were established: complete response (CR) and no change (NC). The Kyoto Encyclopedia of Genes and Genomes pathway analysis showed that cancer-related genes and infection-related genes were highly expressed in the NC and CR groups, respectively. Based on this finding and transcription factor, gene ontology enrichment, and protein-protein interaction analyses, we selected 16 candidate genes for predicting eradication therapy efficacy. Real-time PCR validation in 36 Hp-negative patients showed significantly higher expression of olfactomedin-4 (OLFM4) and the Nanog homeobox (NANOG) in the CR and NC groups, respectively. OLFM4 and NANOG could be positive and negative predictive markers, respectively, for eradication therapy efficacy against gastric MALT lymphoma that is negative for both API2-MALT1 and Hp infection.

Helicobacter pylori-Negative Gastric Mucosa-Associated Lymphoid Tissue Lymphoma Presenting as Massive Gastrointestinal Bleed

This case reports a patient that represents the minority of patients with gastric mucosa-associated lymphoid tissue (MALT) lymphoma who do not have underlying Helicobacter pylori gastritis. Gastric MALT lymphoma is a type of primary gastric lymphoma (PGL), which are extremely rare gastric malignancies characterized by proliferation of B-cells and infiltration of lymphoid tissue leading to destruction of gastric glands. Development of gastric MALT lymphoma is associated with H. pylori gastritis. Patients typically present with a wide range of symptoms including but not limited to epigastric pain, weight loss, gastrointestinal bleeding and gastric wall perforation. Gastric MALT lymphoma presenting as a massive gastrointestinal bleed is quite rare and only a few cases have been documented. Our case demonstrates that it is important to recognize that acute presentations of this disease may also occur. 

Bacterial infection-driven lymphomagenesis

PURPOSE OF REVIEW

The first convincing evidence for a causal relationship between bacterial infection and lymphomagenesis came from the link between gastric lymphoma and chronic Helicobacter pylori gastritis. This review will summarize the current epidemiological, clinical, and biological evidence of a causative role of bacteria in the development of malignant lymphomas, particularly, the extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue type.

RECENT FINDINGS

Other microorganisms have been associated with specific extranodal lymphoma sites with variable and not always definitive, evidence, including Chlamydia psittaci , Borrelia burgdorferi , Campylobacter jejuni and, most recently, Coxiella Burnetii . According to most plausible models, lymphoma growth is a consequence of continuous antigenic stimulation induced by chronic infection. However, some evidence of a direct oncogenic role of H. pylori has been provided, too.

SUMMARY

Lymphomas are not the result of a single cause but multifactorial diseases, influenced by a variety of genetic and environmental elements. Hence, ascertaining the specific contribution of bacterial infections is not always easy. Nevertheless, the eradication of the associated chronic infection may result in sustained lymphoma regression. Moreover, the association between infections and lymphoma may offer opportunities for reducing lymphoma incidence by preventing the predisposing infections or treating them early.

Management of Extranodal Marginal Zone Lymphoma: Present and Upcoming Perspectives

Simple Summary

Extranodal marginal zone lymphoma distinguishes itself from other indolent lymphomas due to its unique pathophysiology and natural history. This is reflected in its management, where next to traditional treatment strategies such as observation, radiotherapy or chemotherapy, eradication of the causal agent and even surgery represent important aspects of therapy. This review focuses on the particular aspects of this indolent lymphoma that affect management and summarizes the current evidence and different guidelines.

Abstract

Extranodal marginal zone lymphoma (EMZL) encompasses a subgroup of non-Hodgkin lymphomas that often present with localized involvement and may manifest in a diversity of organs and tissues. EMZL pathogenesis is in some cases linked to chronic inflammation/infection, which may impose additional diagnostic and clinical challenges. The most studied and established connection is the presence of Helicobacter pylori in gastric EMZL. Due to its heterogeneity of presentation and intricate pathological features, treatment can be complex, and staging systems are decisive for the choice of therapy. Nevertheless, there is no consensus regarding the most suitable staging system, and recommendations vary among different countries. As a rule of thumb, in limited stages, a local therapy with surgery or radiation is the preferred option, and it is potentially curative. Of note, eradicating the causal agent may be an important step of treatment, especially in gastric EMZL, in which Helicobacter pylori eradication remains the first-line therapy for the majority of patients. In patients with more advanced stages, watch-and-wait is a valuable option, especially amongst those without clear indications for systemic therapy, and it may be carried on for several years. If watch-and-wait is not an option, systemic therapy may be needed. Even though several agents have been tested as monotherapy or in combination in recent years, there is no consensus regarding the first-line therapy, and decisions can vary depending on individual factors, such as age, clinical performance and stage. This review aims to discuss the several aspects of EMZL, including genetic milieu, pathogenesis and staging systems, that may influence the choice of therapy. In addition, we present a summary of evidence of several systemic therapies, compare different recommendations worldwide and discuss future perspectives and novelties in its therapy.

Investigation of endoscopic findings in nine cases of Helicobacter suis-infected gastritis complicated by gastric mucosa-associated lymphoid tissue lymphoma

BACKGROUND

We have previously reported that eradication therapy was more effective against Helicobacter pylori (Hp)-negative gastric mucosa-associated lymphoid tissue (MALT) lymphoma in non-Helicobacter pylori Helicobacter (NHPH)-positive cases than in NHPH-negative cases and that the infection status of NHPH could be a predictive marker for the efficacy of eradication therapy for H. pylori negative gastric MALT lymphoma. However, a diagnostic test for NHPH infection has not yet been clinically established. In this study, we investigated the endoscopic findings in cases of H. suis-infected gastritis associated with gastric MALT lymphoma reported at our institution.

MATERIALS AND METHODS

Participants were selected from cases of gastric MALT lymphoma who underwent esophagogastroduodenoscopy at Hiroshima University Hospital, who were negative for the API2-MALT1 gene, and who received eradication therapy as a first-line treatment. We examined the endoscopic findings in nine cases from this group in which H. suis infection was confirmed by polymerase chain reaction.

RESULTS

Endoscopic findings, such as cracked mucosa, spotty redness, nodular gastritis-like appearance, and white marbled appearance, which have been reported as characteristics of NHPH gastritis, were observed in multiple cases. The most common endoscopic findings in this study were cracked mucosa (7/9 cases), followed by spotty redness (6/9 cases), nodular gastritis-like appearance (5/9 cases), and white marbled appearance (2/9 cases).

CONCLUSIONS

Our study may serve as a reference for re-evaluation of the diagnostic criteria for H. suis infection and indications for eradication therapy, particularly for cases of H. pylori negative gastric MALT lymphoma, where endoscopic findings such as those seen in this study were observed in the background mucosa.

Current Status of the Spectrum and Therapeutics of Helicobacter pylori-Negative Mucosa-Associated Lymphoid Tissue Lymphoma

Simple Summary

The prevalence of Helicobacter pylori (HP)-negative gastric mucosa-associated lymphoid tissue (MALT) lymphoma has increased over the last two decades, whereas that of HP-positive gastric MALT lymphoma has decreased. Although the role of first-line antibiotics in the treatment of HP-negative gastric MALT lymphomas remains ambiguous, several case series have reported that a first-line HP eradication therapy (HPE)-like regimen could result in complete remission in a proportion of patients with localized HP-negative gastric MALT lymphoma. Previous sporadic reports have indicated that certain patients with extragastric MALT lymphoma can respond to first-line antibiotic treatment as well. These findings suggest that, in contrast to antibiotic-unresponsive tumors, antibiotic-responsive tumors may be recognized within the spectrum of HP-negative MALT lymphoma. In addition to conventional chemotherapy and immunochemotherapy, macrolide antibiotics and immunomodulatory drugs have been previously used and demonstrated to be efficacious. This article provides the spectrum and therapeutics for HP-negative MALT lymphoma.

Abstract

Helicobacter pylori (HP)-unrelated mucosa-associated lymphoid tissue (MALT) lymphoma includes the majority of extragastric MALT lymphomas and a small proportion of gastric MALT lymphomas. Although the role of first-line antibiotics in treating HP-negative gastric MALT lymphomas remains controversial, HP eradication therapy (HPE)-like regimens may result in approximately 20–30% complete remission (CR) for patients with localized HP-negative gastric MALT lymphoma. In these patients, H. heilmannii, H. bizzozeronii, and H. suis were detected in sporadic gastric biopsy specimens. Extragastric MALT lymphoma is conventionally treated with radiotherapy for localized disease and systemic chemotherapy for advanced and metastatic diseases. However, a proportion of extragastric MALT lymphomas, such as ocular adnexal lesions and small intestinal lesions, were reported to be controlled by antibiotics for Chlamydophila psittaci and Campylobacter jejuni, respectively. Some extragastric MALT lymphomas may even respond to first-line HPE. These findings suggest that some antibiotic-responsive tumors may exist in the family of HP-negative MALT lymphomas. Two mechanisms underlying the antibiotic responsiveness of HP-negative MALT lymphoma have been proposed. First, an HPE-like regimen may eradicate the antigens of unknown bacteria. Second, clarithromycin (the main component of HPE) may have direct or indirect antineoplastic effects, thus contributing to the CR of these tumors. For antibiotic-unresponsive HP-negative MALT lymphoma, high-dose macrolides and immunomodulatory drugs, such as thalidomide and lenalidomide, have reported sporadic success. Further investigation of new treatment regimens is warranted.

[Gastric MALT lymphoma - from pathogenetic insights to consequent deescalation of therapy]

Gastric MALT- (mucosa-associated-lymphoid-tissue) lymphoma represents the most frequent gastrointestinal lymphoma. For decades, surgery and later on radiation and chemotherapy were regarded as established therapy. Some 30 years ago, the pathogenetic role of Helicobacter pylori infection for the development of gastric MALT-lymphoma became evident. During the following years, the pathogenetic insights were consequently implemented into clinical medicine. This lead to a radical change of the therapeutic approach to these lymphoma. Nowadays, Helicobacter pylori eradication is the internationally established therapy of first choice. It is followed by lymphoma regression in most cases. The long-term prognosis of patients after exclusive eradication therapy is excellent, even if endoscopic and/or histological residuals persist and a watch-and-wait strategy is favored.The pathogenetic insights und their clinical application implicated a consequent deescalation of therapy of gastric MALT-lymphoma. This review summarizes the single steps of this development and gives a recommendation for the actual management of patients with gastric MALT lymphoma.

What you always wanted to know about gastric MALT-lymphoma: a focus on recent developments

The stomach is the most common site of origin for extranodal lymphomas, with extranodal marginal zone B-cell of the mucosa associated lymphoid tissue (MALT-lymphoma) being the predominant subtype. MALT-lymphoma develops in mucosa associated lymphoid structures acquired by infection or chronic antigenic stimuli and may therefore arise in almost any organ of the human body. In spite of histopathologic similarities between various organs upon first glance, recent findings suggest pronounced differences between different sites, with a variety of features specific to gastric MALT-lymphoma. The objective of this review is to sum up the current knowledge on pathogenesis, molecular pathology, clinical presentation and therapeutic approaches to gastric MALT-lymphoma with in-depth discussion of recent developments.

Gastric MALT-Lymphoma: more than Helicobacter Pylori

In this case report, we describe two cases of gastric mucosaassociated lymphoid tissue (MALT) lymphoma. The first patient, who presented with complaints of indigestion, nausea and epigastralgy, had a solid ulcer on endoscopy. Biopsies showed, next to MALT, presence of Helicobacter Pylori. The second patient was admitted with hematemesis. The multiple ulcerations in his stomach were thought to be cocaine-induced. Only after multiple biopsies the diagnosis of MALT was made. No presence of Helicobacter Pylori could be detected. The first patient was successfully treated with Helicobacter Pylori eradication therapy. Localized radiotherapy resulted in complete remission in our second patient. Hence, in absence of Helicobacter Pylori, more aggressive treatment modalities are needed.

Genetic Characterization and Clinical Features of Helicobacter pylori Negative Gastric Mucosa-Associated Lymphoid Tissue Lymphoma

Simple Summary

The pathogenesis of H. pylori-associated gastric MALT lymphoma has been well characterized, but the genetic basis and clinical features of H. pylori negative gastric cases remain elusive. In the present study, we investigated the genetic profiles of a large series of H. pylori negative gastric MALT lymphoma by targeted sequencing for a panel of genes specifically designed for marginal zone lymphoma, together with assessment of common translocations and comprehensive clinical data. Targeted sequencing confirmed that NF-κB activation is a major driver in the pathogenesis of H. pylori negative MALT lymphoma, as shown by frequent TNFAIP3 inactivating mutations and also by translocations of MALT1/IGH. This study adds new insights into the genetic background of H. pylori negative MALT lymphoma and will potentially allow us to more specifically target the underlying molecular pathways in future therapeutic concepts.

Abstract

Background: In Western countries, the prevalence of gastric mucosa-associated lymphoid tissue (MALT) lymphoma has declined over the last three decades. Contemporaneously, H. pylori negative gastric MALT lymphoma is increasingly encountered, and their genetic basis and clinical features remain elusive. Methods: A total of 57 cases of H. pylori negative gastric MALT lymphoma were reviewed and investigated for chromosome translocation by fluorescence in-situ hybridization and for somatic mutations by the targeted sequencing of 93 genes. Results: MALT1 translocation, most likely t(11;18)(q21;q21)/BIRC3-MALT1, was detected in 39% (22/57) cases, and IGH translocation was further seen in 12 MALT1-negative cases, together accounting for 60% of the cohort. Targeted sequencing was successful in 35 cases, and showed frequent mutations in NF-κB signaling pathways (TNFAIP3 = 23%, CARD11 = 9%, MAP3K14 = 9%), together affecting 14 cases (40%). The NF-κB pathway mutations were mutually exclusive from MALT1, albeit not IGH translocation, altogether occurring in 86% of cases. There was no significant correlation between the genetic changes and clinicopathological parameters. The patients showed a median of progression-free survival (PFS) of 66.3 months, and a significant superior PFS when treated with systemic versus antibiotic therapy (p = 0.004). Conclusion: H. pylori negative gastric MALT lymphoma is characterized by highly frequent genetic changes in the NF-κB signaling pathways.

Efficacy of eradication therapy in Helicobacter pylori-negative gastric mucosa-associated lymphoid tissue lymphoma: A meta-analysis

BACKGROUND AND AIMS

The role of eradication therapy in Helicobacter pylori-negative gastric mucosa-associated lymphoid tissue (MALT) lymphoma remains controversial. The aim of this study was to investigate the efficacy of H. pylori eradication therapy as a first-line treatment for H. pylori-negative gastric MALT lymphoma.

METHODS

A literature search of studies published until October 2019 was performed using electronic databases. Studies that reported treatment response to eradication therapy as an initial treatment for patients with H. pylori-negative gastric MALT lymphoma were eligible for inclusion. The primary outcome was the complete remission rate after eradication therapy.

RESULTS

Twenty-five studies were included in the analyses. The overall pooled complete remission rate was 29.3% (95% confidence interval [CI], 22.2%-37.4%, I²  = 41.5%). There was no publication bias, and the sensitivity analyses showed consistent results. The pooled complete remission rates were lower in the subgroups of studies that had a higher incidence of translocation t(11;18)(q21;q21) (19.9%, 95% CI, 11.6%-32.0%), studies that used serological tests to exclude H. pylori infection (27.5%, 95% CI, 20.1%-36.4%), and studies where non-response to eradication therapy was determined at <12 months after treatment (27.0%, 95% CI, 15.5%-42.7%). Meta-regression analysis revealed that the pooled estimate was not significantly different in terms of the characteristics of individual studies.

CONCLUSIONS

Although the complete remission rate after eradication therapy is not high, it can be used as an initial treatment option in a subset of patients with H. pylori-negative gastric MALT lymphoma. Further studies to identify subgroups of patients who may benefit from eradication therapy are needed.

The clinical potential of circulating immune cell counts in primary gastric lymphoma

Background

High neutrophil-lymphocyte ratio (NLR) is linked to poor overall survival (OS) in gastrointestinal tract cancers. This study explores the clinical value of NLR, in addition to absolute lymphocyte count (ALC) and other hematologic parameters in association with distant metastases and OS in primary gastric lymphoma (PGL) patients.

Methods

Clinical data of 139 PGL patients who received treatment at King Hussein Cancer Center (KHCC), Amman-Jordan were retrospectively evaluated. Using data from complete blood count (CBC) tests, the following hematologic parameters: absolute neutrophil count (ANC), ALC, absolute eosinophil count (AEC), absolute monocyte count (AMC), NLR, platelet-lymphocyte ratio (PLR), and monocyte-lymphocyte ratio (MLR) were assessed in association with the following clinical outcomes: presence or absence of baseline distant metastases and OS. We conducted univariate and multivariate analyses assessing the various hematologic parameters in association with distant metastases.

Results

Univariate and multivariate analyses indicated that patients with an elevated NLR (>3.14) displayed more baseline distant metastases compared to patients with a low NLR (≤3.14), (P value: 0.02 and 0.018, respectively). High baseline ALC (>1,819/µL) was associated with lower baseline distant metastases (P value: 0.04). In the OS analysis, high baseline ANC (>5,100/µL), NLR (>2.75), and PLR (>0.16) were associated with poor OS, (P value: 0.027, 0.016, and 0.011 respectively).

Conclusions

High NLR and ALC were associated with baseline distant metastases. High baseline ANC, NLR, and PLR were associated with poor OS. Hematologic parameters might be potentially helpful in assessing and correlating NLR with the response success to treatment in PGL.

Quadruple therapy for gastric high-grade B-cell lymphoma

Most low-grade gastric lymphomas arising from the mucosa-associated lymphoid tissue (MALT) are directly related to Helicobacter pylori infection. Most cases of MALT lymphoma limited to the stomach can be cured with H. pylori eradication and remain in remission for years. In contrast, high-grade lymphomas of the stomach, although potentially related to H. pylori, do not usually respond to H. pylori eradication. Here, we present the case of a woman with high-grade diffuse large B-cell lymphoma who achieved complete remission following H. pylori eradication.

[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.

Heterogeneity of clinical management of low-grade gastric lymphoma of mucosa-associated lymphoid tissue. An audit of 198 patients in Spain

INTRODUCTION

Cure of Helicobacter pylori infection in patients with gastric lymphoma of mucosa-associated lymphoid tissue (MALT) leads to long-term clinical remission in the initial stages. As it is a rare disease, its management in clinical practice remains largely unknown and heterogeneity of care remains a concern. The aim was to audit the management and evolution of a large series of low-grade gastric MALT lymphomas from thirteen Spanish hospitals.

MATERIALS AND METHODS

Multicentre retrospective study including data on the diagnosis and follow-up of patients with gastric low-grade MALT lymphoma from January 1998 to December 2013. Clinical, biological and pathological data were analyzed and survival curves were drawn.

RESULTS

One-hundred and ninety-eight patients were included. Helicobacter pylori was present in 132 (69%) patients and 103 (82%) in tumors confined to the stomach (stage EI) and was eradicated in 92% of patients. Chemotherapy was given in 90 (45%) patients and 43 (33%) with stage EI. Marked heterogeneity in the use of diagnostic methods and chemotherapy was observed. Five-year overall survival was 86% (89% in EI). Survival was similar in EI patients receiving aggressive treatment and in those receiving only antibiotics (p=0.577).

DISCUSSION

Gastric MALT lymphoma has an excellent prognosis. We observed, however, a marked heterogeneity in the use of diagnostic methods or chemotherapy in early-stage patients.

The Epidemiology of Gastric Cancers in the Era of Helicobacter pylori Eradication: A Nationwide Cancer Registry-Based Study in Taiwan

BACKGROUND

Helicobacter pylori eradication has been shown to decrease gastric adenocarcinoma risk. The epidemiology of gastric lymphoma, which is also associated with H. pylori, and other rare subtypes of gastric cancer is less clear. This study comprehensively evaluated the incidence trend and the survival of gastric cancer in Taiwan by histologic subtype.

METHODS

The incidence trends of gastric cancer in Taiwan from 1996 and 2013 were evaluated using data from the Taiwan Cancer Registry. The life-table method and the Cox proportional hazards analysis were used to evaluate the survival of gastric cancer.

RESULTS

The incidence of all gastric cancers in Taiwan decreased from 15.97 per 100,000 in 1996 to 11.57 per 100,000 in 2013. The most frequent histologic subtype of gastric cancer in Taiwan was adenocarcinoma, followed by lymphoma and sarcoma (mainly gastrointestinal stromal tumor). The best survival was in patients with sarcoma, followed by lymphoma, neuroendocrine tumor, and adenocarcinoma. Generally, women had a better survival than men. The incidence of adenocarcinoma significantly decreased from 13.56 per 100,000 in 1996 to 9.82 per 100,000 in 2013 (P < 0.0001). In contrast, the incidences of mucosa-associated lymphoid tissue lymphoma and diffuse large B-cell lymphoma did not decrease.

CONCLUSIONS

The incidence of adenocarcinoma and lymphoma, both of which are associated with H. pylori, showed diverging trends. The survival of gastric cancer differed by histologic subtype and sex.

IMPACT

The disparity in the incidence trends between gastric lymphoma and adenocarcinoma, both associated with H. pylori, warranted the need to search for additional risk factors of gastric lymphoma.

Novel Insights of Lymphomagenesis of Helicobacter pylori-Dependent Gastric Mucosa-Associated Lymphoid Tissue Lymphoma

Gastric mucosa-associated lymphoid tissue (MALT) lymphoma is the most common subtype of gastric lymphoma. Most gastric MALT lymphomas are characterized by their association with the Helicobacter pylori (HP) infection and are cured by first-line HP eradication therapy (HPE). Several studies have been conducted to investigate why most gastric MALT lymphomas remain localized, are dependent on HP infection, and show HP-specific intratumoral T-cells (e.g., CD40-mediated signaling, T-helper-2 (Th2)-type cytokines, chemokines, costimulatory molecules, and FOXP3+ regulatory T-cells) and their communication with B-cells. Furthermore, the reason why the antigen stimuli of these intratumoral T-cells with tonic B-cell receptor signaling promote lymphomagenesis of gastric MALT lymphoma has also been investigated. In addition to the aforementioned mechanisms, it has been demonstrated that the translocated HP cytotoxin-associated gene A (CagA) can promote B-cell proliferation through the activation of Src homology-2 domain-containing phosphatase (SHP-2) phosphorylation-dependent signaling, extracellular-signal-regulated kinase (ERK), p38 mitogen-activated protein kinase (MAPK), B-cell lymphoma (Bcl)-2, and Bcl-xL. Furthermore, the expression of CagA and these CagA-signaling molecules is closely associated with the HP-dependence of gastric MALT lymphomas (completely respond to first-line HPE). In this article, we summarize evidence of the classical theory of HP-reactive T-cells and the new paradigm of direct interaction between HP and B-cells that contributes to the HP-dependent lymphomagenesis of gastric MALT lymphomas. Although the role of first-line HPE in the treatment of HP-negative gastric MALT lymphoma remains uncertain, several case series suggest that a proportion of HP-negative gastric MALT lymphomas remains antibiotic-responsive and is cured by HPE. Considering the complicated interaction between microbiomes and the genome/epigenome, further studies on the precise mechanisms of HP- and other bacteria-directed lymphomagenesis in antibiotic-responsive gastric MALT lymphomas are warranted.

Management of relapsed/refractory marginal zone lymphoma: focus on ibrutinib

Marginal zone lymphomas (MZLs) consist of a diverse family of malignancies, which are derived from B-cells. The disease subtypes are recognized extranodal, nodal, and splenic MZLs. The disease characteristics, clinical course, and treatment vary considerably based on the site of involvement. In 2017, the US Food and Drug Administration approved ibrutinib, a first in class Bruton’s tyrosine kinase inhibitor that revolutionized the care of chronic lymphocytic leukemia patients; for, the treatment of relapsed/refractory MZL based on pivotal open-label Phase II trial demonstrated an overall response rate of 48%, with a complete response rate of 3%, median progression-free survival of 14.2 months, and median overall survival not yet reached at a median follow-up of 19.4 months. In this review, we aim to summarize the current conundrums in the management of MZL and the evolving role of ibrutinib in the treatment of MZL.

First-line antibiotic therapy in Helicobacter pylori-negative low-grade gastric mucosa-associated lymphoid tissue lymphoma

First-line antibiotic treatment for eradicating Helicobacter pylori (HP) infection is effective in HP-positive low-grade gastric mucosa-associated lymphoid tissue lymphoma (MALToma), but its role in HP-negative cases is uncertain. In this exploratory retrospective study, we assessed the outcome and potential predictive biomarkers for 25 patients with HP-negative localized gastric MALToma who received first-line HP eradication (HPE) therapy. An HP-negative status was defined as negative results on histology, rapid urease test, ¹³C urea breath test, and serology. We observed an antibiotic response (complete remission [CR], number = 8; partial remission, number = 1) in 9 (36.0%) out of 25 patients. A t(11;18)(q21;q21) translocation was detected in 7 (43.8%) of 16 antibiotic-unresponsive cases, but in none of the 9 antibiotic-responsive cases (P = 0.027). Nuclear BCL10 expression was significantly higher in antibiotic-unresponsive tumors than in antibiotic-responsive tumors (14/16 [87.5%] vs. 1/9 [11.1%]; P = 0.001). Nuclear NF-κB expression was also significantly higher in antibiotic-unresponsive tumors than in antibiotic-responsive tumors (12/16 [75.0%] vs. 1/9 [11.1%]; P = 0.004). A substantial portion of patients with HP-negative gastric MALToma responded to first-line HPE. In addition to t(11;18)(q21;q21), BCL10 and NF-κB are useful immunohistochemical biomarkers to predict antibiotic-unresponsive status in this group of tumors.

Helicobacter pylori Eradication Therapy Is Effective as the Initial Treatment for Patients with H. pylori-Negative and Disseminated Gastric Mucosa-Associated Lymphoid Tissue Lymphoma

BACKGROUND/AIMS

We investigated the effectiveness of Helicobacter pylori eradication therapy for gastric mucosaassociated lymphoid tissue (MALT) lymphoma regardless of the H. pylori infection status or disease stage.

METHODS

From November 1995 to September 2014, 345 subjects who were diagnosed with gastric MALT lymphoma and had received eradication therapy as their first-line treatment were eligible for inclusion in this study. A retrospective review was performed using the medical records.

RESULTS

Of the 345 patients, H. pylori infection was detected in 317 patients (91.9%). The complete remission (CR) rate after eradication therapy was 82.3%, which was higher in H. pylori -positive patients than in H. pylori-negative patients (84.5% vs 57.1%, p=0.001). CR rates after eradication did not present significant differences between stages, and the CR rate was 83.3% for stage IE1 and 74.4% for stage IE2 or above (p=0.167). The overall CR rate was 87.2% after additional treatment, and neither H. pylori infection status nor stage showed differences according to the treatment response.

CONCLUSIONS

Eradication therapy led to CR in 57.1% of H. pylori-negative patients and in 74.4% of patients with stage IE2 or above. Eradication therapy is worthwhile as an initial treatment for gastric MALT lymphoma regardless of the H. pylori infection status and stage.

Clinical aspects and therapy of gastrointestinal MALT lymphoma

Extranodal marginal zone B-cell lymphomas of the mucosa associated lymphoid tissue (MALT) arise from lymphoid populations that are induced by chronic inflammation in extranodal sites. Among the MALT lymphomas, gastrointestinal (GIT) MALT lymphoma is the most frequent compared to non-GIT MALT lymphoma arising from other sites. Gastric MALT lymphoma has been the first to be described with the evidence of an etiopathogenetic link provided by the association between Helicobacter pylori-positive gastritis and gastric MALT lymphoma. Indeed, successful eradication of this micro-organism with antibiotics can be followed by a lymphoma regression in most cases. When there is no association with Helicobacter pylori, there is no clear therapeutic consensus. Both radiotherapy and systemic treatments with chemotherapy and anti-CD20 antibodies are efficacious and thus the experience of individual centers and each patient's preferences in terms of adverse effects are important parameters in the decision process.

Epidemiology and environmental aspects of marginal zone lymphomas

Marginal zone lymphomas (MZLs) account for between 5% and 17% of all non-Hodgkin's lymphomas. MZLs consist of 3 different subtypes with extranodal being the most commonly reported, representing 50-70% of MZL, followed by splenic (20%) and nodal (10%). Median age at presentation varies between these lymphoma sub-types, ranging between 50 and 69 years, with an overall greater incidence noted in males compared to females. Given the rarity of these lymphomas, epidemiologic data has been sparse, although it has been suggested the aetiology is multi-factorial including ethnicity and geographical factors. Other reported associations include autoimmune disease and infection, with Helicobacter pylori and Campylobacter psittaci, being the most commonly reported pathogens. Larger population studies are required to investigate the role of these environmental factors further as these can direct the future management of these lymphomas, through the use of more effective targeted treatments.

[Radiotherapy for localized gastric and orbital MALT lymphomas]

Primary gastric and orbital MALT lymphomas are both low grade (indolent) B-cell non-Hodgkin's lymphomas. Traditionally, these tumors are radiosensitive and have a good prognosis. In localized orbital and stages IE-IIE gastric MALT lymphomas without Helicobacter pylori infection or in case of persistent H. pylori infection after eradication therapy, several retrospective studies have shown that radiotherapy was an effective and well-tolerated treatment.

The spectrum of MALT lymphoma at different sites: biological and therapeutic relevance

Extranodal marginal zone (MZ) B-cell lymphomas of the mucosa-associated lymphoid tissue (MALT) arise from lymphoid populations that are induced by chronic inflammation in extranodal sites. The best evidence of an etiopathogenetic link is provided by the association between Helicobacter pylori–positive gastritis and gastric MALT lymphoma. Indeed, successful eradication of this microorganism with antibiotics can be followed by gastric MALT lymphoma regression in most cases. Other microbial agents have been implicated in the pathogenesis of MZ lymphoma arising at different sites. Apart from gastric MALT lymphoma, antibiotic therapies have been adequately tested only in ocular adnexal MALT lymphomas where upfront doxycycline may be a reasonable and effective initial treatment of patients with Chlamydophila psittaci–positive lymphoma before considering more aggressive strategies. In all other instances, antibiotic treatment of nongastric lymphomas remains investigational. Indeed, there is no clear consensus for the treatment of patients with gastric MALT lymphoma requiring further treatment beyond H pylori eradication or with extensive disease. Both radiotherapy and systemic treatments with chemotherapy and anti-CD20 antibodies are efficacious and thus the experience of individual centers and each patient’s preferences in terms of adverse effects are important parameters in the decision process.

Clinicopathologic characteristics and treatment of marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT lymphoma)

Extranodal marginal zone lymphoma of the mucosa-associated lymphoid tissue (MALT lymphoma) accounts for 7% to 8% of newly diagnosed lymphomas. Because of its association with infectious causes, such as Helicobacter pylori (HP) or Chlamydophila psittaci (CP), and autoimmune diseases, it has become the paradigm of an antigen-driven malignancy. MALT lymphoma usually displays an indolent course, and watch-and-wait strategies are justified initially in a certain percentage of patients. In patients with gastric MALT lymphoma or ocular adnexal MALT lymphoma, antibiotic therapy against HP or CP, respectively, is the first-line management of choice, resulting in lymphoma response rates from 75% to 80% after HP eradication and from 33% to 65% after antibiotic therapy for CP. In patients who have localized disease that is refractory to antibiotics, radiation is widely applied in various centers with excellent local control, whereas systemic therapies are increasingly being applied, at least in Europe, because of the potentially systemic nature of the disease. Therefore, the objective of this review is to briefly summarize the clinicopathologic characteristics of this distinct type of lymphoma along with current data on management strategies.

Clinical Outcome of Eradication Therapy for Gastric Mucosa-Associated Lymphoid Tissue Lymphoma according to H. pylori Infection Status

Background. To evaluate the long-term outcome of H. pylori eradication therapy for gastric MALT lymphoma according to the presence of H. pylori infection. Methods. We retrospectively reviewed the medical records of patients between January 2001 and June 2014. The clinicopathologic characteristics and clinical outcomes were compared between H. pylori-positive and H. pylori-negative gastric MALT lymphoma groups. Results. Fifty-four patients were enrolled: 12 H. pylori-negative and 42 H. pylori-positive patients. The tumor was located more frequently in both the proximal and distal parts of the stomach (P = 0.001), and the percentage of multiple lesions was significantly greater in the H. pylori-negative group (P = 0.046). Forty-seven patients received initial eradication therapy, and 85% (35/41) of H. pylori-positive patients and 50% (3/6) of H. pylori-negative patients achieved complete remission after eradication therapy. The presence of multiple lesions was a predictive factor for unresponsiveness to H. pylori eradication (P = 0.024). The efficacy of eradication therapy (P = 0.133), complete remission (CR) maintenance period, and relapse after eradication therapy were not significantly different between the two groups. Conclusions. H. pylori eradication therapy could be an effective first-line treatment for localized H. pylori-negative gastric MALT lymphoma, especially for single lesions.

The role of infectious agents, antibiotics, and antiviral therapy in the treatment of extranodal marginal zone lymphoma and other low-grade lymphomas

OPINION STATEMENT

There is strong evidence to corroborate the association with Helicobacter pylori (Hp) to gastric extranodal marginal zone lymphoma (ENMZL) and hepatitis C virus (HCV) to splenic/nodal marginal zone lymphoma. Koch's postulates generally hold for these two associations and eradication of the infectious agent is well supported. Hp eradication (HPE) is recommended as front-line therapy for early stage gastric ENMZL regardless of Hp status. Complete response (CR) rate for Hp-negative patients is not as high as for Hp-positive patients; however, the benign nature of HPE and high rates of salvage allow this strategy to be safe while sparing some Hp-negative patients from systemic therapy or radiation. Similarly for HCV-seropositive patients, treatment with antivirals should be strongly considered as first-line for those who do not require immediate cytoreductive therapy or at some point even after completing chemoimmunotherapy. The controversy regarding the role for antibiotics is greatest for primary ocular adnexal lymphoma (POAL). Considering the low incidence of Chlamydia psittaci (Cp) infection with OAL and the challenges to reliably identifying Cp, we typically do not consider doxycycline in POAL treatment. Involved-field radiotherapy (IFRT) remains the treatment of choice for most with unilateral POAL. However, if reliable detection of Cp is available and Cp is identified, patients with unilateral low tumor stage POAL who do not require immediate radiotherapy could be considered for doxycycline as front-line treatment. Other infectious associations to indolent lymphomas have been made, including Borrelia borgdorferi (Bb) in cutaneous lymphoma and Campylobacter in immunoproliferative small intestinal disease (IPSID), but these associations are not as strong and primary treatment targeting the infectious agents is not recommended.

Infectious Aetiology of Marginal Zone Lymphoma and Role of Anti-Infective Therapy

Marginal zone lymphomas have been associated with several infectious agents covering both viral and bacterial pathogens and in some cases a clear aetiological role has been established. Pathogenetic mechanisms are currently not completely understood. However, the role of chronic stimulation of the host immune response with persistent lymphocyte activation represents the most convincing explanation for lymphoproliferation. Gastric MALT lymphoma is strictly associated with Helicobacter pylori infection and various eradicating protocols, developed due to increasing antibiotic resistance, represent the first line therapy for gastric MALT. The response rate to eradication is good with 80% of response at 1 year; this finding is also noteworthy because it recapitulates cancer cured only by the antibacterial approach and it satisfies the Koch postulates of causation, establishing a causative relationship between Hp and gastric MALT lymphoma. Patients with chronic HCV infection have 5 times higher risk to develop MZL, in particular, an association with splenic and nodal MZL has been shown in several studies. Moreover, there is evidence of lymphoma regression after antiviral therapy with interferon+ribavirin, thus raising hope that newly available drugs, extremely efficient against HCV replication, could improve outcome also in HCV-driven lymphomas. Another case-study are represented by those rare cases of MZL localized to orbital fat and eye conjunctivas that have been associated with Chlamydophila psittaci infection carried by birds. Efficacy of antibacterial therapy against C. psittaci are conflicting and generally poorer than gastric MALT. Finally, some case reports will cover the relationship between primary cutaneous B-cell Lymphomas and Borrelia Burgdorferi.

Gastric malt lymphoma: Analysis of a series of consecutive patients over 20 years

INTRODUCTION AND AIMS

Gastric mucosa-associated lymphoid tissue (MALT) lymphoma is closely associated with Helicobacter pylori (HP) infection. Our aim was to evaluate demographic, clinical and endoscopic characteristics of gastric MALT lymphoma patients, as well as to analyse response to treatment and factors that affect complete remission (CR) and relapse. We also assessed the long-term prognosis.

METHODS

The study involved a retrospective evaluation of consecutive patients admitted with gastric MALT lymphoma (1993-2013).

RESULTS

A total of 144 patients (76 men; mean age 56) were included. At stage EI, 94/103 patients (92%) received HP eradication and 78 (83%) achieved CR after a mean period of 7 months (2-63 months) and 67 (86%) remained in CR after a mean follow-up time of 105 months. HP infection status (p = 0.004) and lymphoma localisation to the antrum plus body (p = 0.016) were associated with higher and lower CR rates, respectively. Relapse occurred in 11/78 (14%) patients after a mean period of 21 months. The absence of HP re-infection (p = 0.038), the need of only one eradication regimen (p = 0.009) and antrum lymphomas (p = 0.031) correlated with lower relapse rates. At stage EII, HP eradication was performed in 17/24 patients but only five experienced CR (30%). Among 16 patients diagnosed at stage EIV, nine achieved CR after chemotherapy ± surgery and 3/7 without remission died due to disease progression. The 5- and 10-year overall disease free survival rates were 90.5% and 79.1%, respectively.

CONCLUSIONS

Most patients were diagnosed at an early stage. Eradication therapy was highly effective in inducing complete remission. Long-term evaluation showed that the long-term prognosis was very favourable.

Survival of patients with gastric lymphoma in Germany and in the United States

BACKGROUND AND AIM

This study aims to examine survival for gastric lymphomas and its main subtypes, mucosa-associated lymphoid tissue lymphoma (MALT), and diffuse large B-cell lymphoma (DLBCL), in Germany and in the United States.

METHODS

Data for patients diagnosed in 1997-2010 were used from 10 population-based German cancer registries and compared to the data from the US Surveillance, Epidemiology and End Results (SEER) 13 registries database. Patients age 15-74 diagnosed with gastric lymphomas were included in the analysis. Period analysis and modeled period analysis were used to estimate 5-year and 10-year relative survival (RS) in 2002-2010 and survival trends from 2002-2004 to 2008-2010.

RESULTS

Overall, the database included 1534 and 2688 patients diagnosed with gastric lymphoma in 1997-2010 in Germany and in the United States, respectively. Survival was substantially higher for MALT (5-year and 10-year RS: 89.0% and 80.9% in Germany, 93.8% and 86.8% in the United States) than for DLBCL (67.5% and 59.2% in Germany, and 65.3% and 54.7% in the United States) in 2002-2010. Survival was slightly higher among female patients and decreased by age for gastric lymphomas combined and its main subtypes. A slight, nonsignificant, increase in the 5-year RS for gastric lymphomas combined was observed in Germany and the United States, with increases in 5-year RS between 2002-2004 and 2008-2010 from 77.1% to 81.0% and from 77.3% to 82.0%, respectively. Five-year RS of MALT exceeded 90% in 2008-2010 in both countries.

CONCLUSIONS

Five-year RS of MALT meanwhile exceeds 90% in both Germany and the United States, but DLBCL has remained below 70% in both countries.

Treatment Strategy for Gastric Mucosa-Associated Lymphoid Tissue Lymphoma

Recent trends and current knowledge on the diagnosis and treatment strategy for gastric mucosa-associated lymphoid tissue (MALT) lymphoma are reviewed. Helicobacter pylori infection plays the causative role in the pathogenesis, and H pylori eradication is the first-line treatment of this disease, which leads to complete remission in 60% to 90% of cases. A Japanese multicenter study confirmed that the long-term outcome of gastric MALT lymphoma after H pylori eradication is excellent. Treatment strategies for patients not responding to H pylori eradication including "watch and wait" strategy, radiotherapy, chemotherapy, rituximab immunotherapy, and combination of these should be tailored in consideration of the disease extent in each patient.

Helicobacter pylori-negative gastric mucosa-associated lymphoid tissue lymphomas: A review

Since Isaacson and Wright first reported on the extra-nodal marginal zone B-cell lymphoma of the stomach in 1983, following studies have clarified many aspects of this disease. We now know that the stomach is the most affected organ by this disease, and approximately 90% of gastric mucosa-associated lymphoid tissue (MALT) lymphomas are related to Helicobacter pylori (H. pylori) infection. This implies that approximately 10% of gastric MALT lymphomas occur independent of H. pylori infection. The pathogenesis of these H. pylori-negative gastric MALT lymphomas remains unclear. To date, there have been several speculations. One possibility is that genetic alterations result in nuclear factor-kappa B (NF-κB) activation. Among these alterations, t(11;18)(q21;q21) is more frequently observed in H. pylori-negative gastric MALT lymphomas, and such translocation results in the synthesis of fusion protein API2-MALT1, which causes canonical and noncanonical NF-κB activation. Another possibility is infection with bacteria other than H. pylori. This could explain why H. pylori eradication therapy can cure some proportions of H. pylori-negative gastric MALT lymphoma patients, although the bacteria responsible for MALT lymphomagenesis are yet to be defined. Recent advances in endoscopy suggest magnifying endoscopy with narrow band imaging as a useful tool for both detecting gastric MALT lymphoma lesions and judging the response to treatment. A certain proportion of H. pylori-negative gastric MALT lymphoma patients respond to eradication therapy; hence, H. pylori eradication therapy could be considered as a first-line treatment for gastric MALT lymphomas regardless of their H. pylori infection status.

Antibiotic treatment as sole management of Helicobacter pylori-negative gastric MALT lymphoma: a single center experience with prolonged follow-up

Relatively little is known about the long-term outcome of patients with Helicobacter pylori (HP)-negative gastric lymphoma of mucosa-associated lymphoid tissue (MALT lymphoma) with antibiotic therapy as sole management. We have analyzed all patients with HP-negative gastric MALT lymphoma undergoing antibiotic therapy as sole management of their disease. HP negativity was defined as negative histology, breath test and serology, and response to treatment, survival and long-term outcome was assessed together with clinico-pathological characteristics including t(11; 18) (q21; q21) translocation. Out of 97 patients with gastric MALT lymphoma, 24 were HP-negative, and 13 (5 females and 8 males) underwent only antibiotic management for initial therapy. Eight had stage I and five were found to have stage II disease, with three patients suffering from an underlying autoimmune disease. Antibiotic therapy consisted of standard HP eradication regimens consisting of clarithromycin in all patients, along with metronidazole in seven and amoxicillin in six plus a proton-pump inhibitor. After a median follow-up of 95 months (42-, 181+), 12/13 patients are alive. Six patients with stage I disease achieved an objective response (five complete (CR) and one partial remission, 46 %), four had stable disease (lasting 11-27 months), and three progressed. All patients with stable disease received chemotherapy, but only one patient due to clear cut progression. One patient relapsed 23 months after initial CR, and achieved a second CR with antibiotics now lasting 87 months. These results indicate that a relevant percentage of patients with HP-negative gastric MALT lymphoma may benefit from antibiotic therapy and do not require additional oncological therapies. Our data suggest that the remissions seen in these patients might be durable as evidenced by prolonged follow-up in our series.

Management of gastric mucosa-associated lymphoid tissue lymphoma

Extranodal marginal zone lymphomas of mucosa-associated lymphoid tissue (MALT) type represent 7-8% of all B cell lymphomas and up to 50% of primary gastric lymphomas and can arise at any extranodal site. The most common manifestation is the stomach, which is almost invariably associated with a chronic Helicobacter pylori infection. The diagnosis is based on the histopathological evaluation of multiple gastric biopsies in accordance with the current WHO classification. The mainstay of therapy is H. pylori eradication, which must be delivered to all gastric MALT lymphoma patients, independent of stage. In patients who do not achieve lymphoma regression following antibiotic therapy, irradiation and/or systemic oncological therapies should be applied, depending on the stage of the disease. Radiotherapy might be the preferred option for localized stage. However, in the presence of disseminated or advanced disease, chemotherapy and/or immunotherapy with the anti-CD 20 antibody rituximab is the treatment of choice, but no standard chemotherapy has been defined so far. Gastric MALT lymphomas have a limited tendency to distant spreading and to histological transformation and thus MALT lymphoma usually has a favorable outcome, with an overall survival rate at 5 years of more than 85%.

Gastric MALT lymphoma - update on diagnosis and treatment

Gastrointestinal lymphoma represent a heterogenous group with differences in pathogenesis, treatment and prognosis. Gastric MALT lymphoma is the most common entity. Helicobacter pylori has been identified as its decisive pathogenetic factor. Once a definitive diagnosis has been established a staging procedure is obligatory for defining the stage of disease. H. pylori eradication is the treatment of choice in all MALT lymphoma patients being infected by the bacterium. In some 70-80% of patients with stages I/II complete regression of the lymphoma will develop after successful eradication of H. pylori. Another 20% of patients will reveal minimal histological residuals after eradication. They can be successfully managed by a watch-and-wait strategy if initial endoscopic abnormalities disappear. At present, it is unclear if this strategy can be also offered to patients with persisting minimal endoscopic abnormalities. Why eradication therapy is effective in some patients with negative H. pylori status is highly speculative at present. Non-responders to H. pylori therapy are transferrred to radiotherapy in stages I/II or to immuno-chemotherapy in stages III/IV.