Chlorambucil versus observation after anti-Helicobacter therapy in gastric MALT lymphomas: results of the international randomised LY03 trial

Clinical relevance of molecular aspects in extranodal marginal zone lymphoma: a critical appraisal

Extranodal marginal zone B-cell lymphoma of the mucosa-associated lymphoid tissue (MALT lymphoma) is among the more common types of lymphoma accounting for up to 8% of newly diagnosed lymphoma cases. As opposed to other B-cell lymphomas, however, no predominant genetic hallmark has been defined in MALT lymphoma, but different localizations appear to be affected by different, sometimes distinct changes. Nonetheless, a high proportion of these genetic changes reported in MALT lymphomas dysregulate the pathways leading to NF-kB activation. t(11;18)(q21;q21)/BIRC3::MALT1 appears to be MALT lymphoma specific and is found in 24% of gastric and 40% of pulmonary MALT lymphomas. The translocation is associated with more disseminated disease in gastric MALT lymphoma and is found in a large percentage of patients whose lymphoma is unresponsive to antibiotic eradication of Helicobacter pylori. In addition to t(11;18)(q21;q21), nuclear expression of BCL10 or NF-kB appears to be highly associated with lymphoma cell survival independence of H. pylori-mediated stimulations. Antibiotic eradication, however, is the recommended therapy of choice irrespective of genetic findings, and molecular analysis is not required before initiation of therapy. The influence of genetic translocations including t(11;18)(q21;q21) on systemic therapies, however, is less clearly defined. While small series have shown no influence on the outcome for treatment with the anti-CD20 antibody rituximab (R) or treatment with cladribine (2-CdA), conflicting data have been reported for alkylating agents, especially chlorambucil and the combination of R + chlorambucil. None of other genetic changes seen in MALT lymphoma to date has discernible value in routine clinical applications, but recent data suggest that changes in TNFAIP3(A20), KMTD2 and CARD11 might be associated with response to Bruton kinase inhibitors.

Positron emission tomography/magnetic resonance imaging (PET/MRI) vs. gastroscopy: Can it improve detection of extranodal marginal zone lymphomas of the stomach following H. pylori treatment?

INTRODUCTION

The stomach is the most common site of origin for extranodal marginal zone B-cell lymphoma of the mucosa-associated lymphoid tissue (MALT lymphoma). Antibiotic eradication of Helicobacter pylori (H. pylori) is the standard first-line treatment, with response assessment being performed by histological evaluation of multiple gastric biopsies.

AREAS COVERED

The objective of this review is to provide an update on results obtained using noninvasive methods, including magnetic resonance imaging (MRI), positron emission tomography combined with computed tomography (PET/CT), and most recently, PET/MRI for the assessment of disease extent and response to treatment in patients with gastric MALT lymphoma.

EXPERT OPINION

While CT is the officially recommended imaging technique, few studies in small cohorts have suggested that diffusion-weighted MRI shows higher sensitivity, also relative to 18 F-FDG PET/CT, for both gastric and nongastric MALT lymphomas. A recent prospective study using PET/MRI with the novel CXCR4-targeting radiotracer 68 Ga-Pentixafor suggested that, for patients with gastric MALT lymphoma after H. pylori eradication, this imaging technique may provide excellent accuracy (97%) for assessment of residual or recurrent disease. Although recent studies on CXCR4-targeting PET and to some extent also diffusion-weighted MRI are promising, there is insufficient evidence to suggest a change in clinical practice.

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.

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.

Azithromycin concentrations during long-term regimen, a pilot study in patients with MALT lymphoma

In view of the antineoplastic effects of the macrolide clarithromycin in mucosa associated lymphatic tissue (MALT)-lymphoma, we performed a pilot study assessing levels of azithromycin in plasma, peripheral blood mononuclear cells (PBMC) and polymorphonuclear leukocytes (PMN) of MALT-lymphoma patients to determine the pharmacokinetics and potential influences of respective concentrations on the therapeutic outcome. In total 16 patients with MALT-lymphoma received 1.5 g of oral azithromycin once-weekly over 6 months. Blood was sampled directly prior to the following dose every 4 weeks during treatment. Drug levels were analysed by high performance liquid chromatography in plasma and intracellularly in PBMC and PMN. They were correlated with patients’ age, weight and body-mass-index and compared between patients responsive or unresponsive to treatment. Mean azithromycin plasma levels of all patients were 58.97 ± 30.48 ng/ml, remaining stable throughout the treatment period. Correlation analysis of plasma azithromycin showed no significance. Intracellular PBMC concentrations were 6648 ± 8479 ng/ml, without any significant difference between responders and non-responders. Mean PMN levels were 39,274 ± 25,659 ng/ml and significantly higher in patients unresponsive to treatment (t = 2.858, p = 0.017). Our drug regime led to continuously high plasma and exceedingly high intracellular concentrations of azithromycin in PBMC and PMN. Age, weight or body-mass-index had no significant influence on plasma levels and thence should not be considered in dosage finding. High AZM levels in PBMC did not lead to a better treatment response, whereas enrichment in PMN suggested a poorer outcome. The threshold for immunomodulatory effects on lymphoma cells might not have been reached. Additionally, the finding of stable plasma and intracellular concentrations over months with high-dose azithromycin administered in intervals might also be important for the further design of azithromycin-based trials against MALT-lymphoma.

Trial registration: EudraCT 2016-001521-13, 14/06/2016.

How can we assess and measure prognosis for MALT lymphoma? A review of current findings and strategies

INTRODUCTION

: MALT (mucosa associated lymphoid tissue) lymphoma is a distinct type of B-cell lymphoma characterized by extranodal manifestation and an indolent clinical course with 10-year survival rates up to 90%. However, transformation to aggressive lymphoma may occur and treatment is indicated in case of symptomatic or progressive disease.

AREAS COVERED

: This review covers clinical and biological features potentially related to prognosis and outcome of MALT lymphoma patients, as well as available prognostic tools and risk stratification systems with a focus on the MALT-IPI (international prognostic index) and the POD24 (progression of disease at 24 months) cohort. In addition, we address the role of watch-and-wait, the importance of defining the optimal time point for treatment initiation and the relevance of depth of remission, which appear to be some of the central questions for physicians involved in the care of MALT lymphoma patients. A computerized database search using PubMed® was performed to identify available publications on prognostic factors and risk stratification tools in MALT lymphoma.

EXPERT OPINION

: Despite the development of disease-specific risk stratification systems, there is no clear concept how to measure prognosis and tailor treatment. Careful observation of the individual clinical course is essential to assess the optimal time point of treatment initiation and avoid overtreatment, particularly in patients with disseminated disease. In addition, early detection of patients with histological transformation is necessary, as these patients face a poor prognosis.

Radiotherapy in Early-stage Gastric MALT: Improved Survival Without Increased Cardiac Death

PURPOSE

Radiotherapy (RT) is an effective treatment for localized gastric mucosa-associated lymphoid tissue (MALT) lymphomas unresponsive to antibiotic therapy; however, irradiating the stomach can result in significant radiation to the heart, a risk factor for cardiac disease. We analyzed the Surveillance, Epidemiology, and End Results database to evaluate outcomes related to cardiac disease among patients treated with RT for stage I gastric MALT.

MATERIALS AND METHODS

We identified adult patients treated between 1993 and 2014. The relationship between treatment modality (RT, chemotherapy, combination, and no treatment) and overall survival (OS), mucosa-associated lymphoid tissue-specific survival (MSS), non-mucosa-associated lymphoid tissue-specific survival (non-MSS), and cardiac-specific survival (CSS) was assessed using the Kaplan-Meier estimator and Cox proportional hazards analyses.

RESULTS

A total of 2996 patients (median follow-up, 5.6 y) were analyzed: 27.5% had received RT alone, 12.1% chemotherapy alone, 3.9% chemoradiotherapy, and 56.5% no/unknown treatment (including antibiotic therapy). Compared with RT alone, patients who received chemotherapy alone exhibited worse OS (hazard ratio [HR]: 1.67; 95% confidence interval [CI]: 1.32-2.10; P<0.001) and MSS (HR: 2.10; 95% CI: 1.36-3.23; P=0.001). Although CSS appeared worse in patients who received chemotherapy (HR: 1.56; 95% CI: 0.92-2.66; P=0.10), it was not statistically significant. When comparing orbital and gastric MALT patients, there was no significant difference in CSS (HR: 0.80; 95% CI: 0.49-1.31; P=0.38).

CONCLUSIONS

RT improved survival among patients with stage I gastric MALT without increasing the risk of cardiac death. Those with gastric MALT exhibited similar CSS to those with orbital MALT. Although we cannot analyze nonfatal cardiac toxicity, these results suggest that, absent antibiotic therapy, RT should remain first-line treatment for early-stage gastric MALT.

Phase II trial evaluating the efficacy and safety of the anti-CD20 monoclonal antibody obinutuzumab in patients with marginal zone lymphoma

Marginal zone lymphoma (MZL) belongs to the group of indolent B-cell non-Hodgkin's lymphomas, which is characterized by an indolent course. In this mostly elderly patient population, the development of chemotherapy-free approaches is of particular interest. In this situation, single-agent treatment with the next-generation anti-CD20 antibody obinutuzumab is an attractive approach, which promises high efficacy without major toxicity. We describe here an open-label, multicentric Phase II trial evaluating the efficacy and safety of obinutuzumab in de novo MZL patients, who are treatment naive for systemic therapy and not eligible for or failed local treatment. ClinicalTrials.gov identifier NCT03322865.

Depth of Remission Following First-Line Treatment Is an Independent Prognostic Marker for Progression-Free Survival in Gastric Mucosa-Associated Lymphoid Tissue (MALT) Lymphoma

Gastric mucosa-associated lymphoid tissue (MALT) lymphoma responding to upfront treatment has an excellent outcome and no further therapy is recommended, even in the presence of residual disease. However, no data exist on the influence of initial depth of remission on progression-free survival (PFS). Methods: We investigated a correlation between PFS and depth of response, categorizing them as complete remission (CR), partial remission (PR) and stable disease (SD) in 137 consecutive patients at the Medical University Vienna. Results: All patients with Helicobacter pylori (H. pylori)-positive, localized disease received H. pylori eradication (70%, 96/137), while the remaining patients were treated with various modalities. The response rate was 67% for the entire collective and 58% for eradication only, with corresponding CR-rates of 48% and 38%. At a median follow-up of 56.2 months, the estimated PFS for the entire cohort was 34.2 months (95% Confidence Interval 16.0–52.4). Responding patients (=CR/PR) had a significantly longer PFS compared to SD (68.3 vs. 17.3 months, p < 0.001). This was also applicable to the eradication only cohort (49.0 vs. 17.3 months, p < 0.001) and remained significant after correction for MALT-IPI. Furthermore, CR significantly prolonged PFS over PR (p = 0.007 entire cohort, p = 0.020 eradication). Conclusions: Remission status correlated significantly with PFS, suggesting depth of remission as prognostic marker for long-term relapse-free survival.

Extranodal marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue in the oromaxillofacial head and neck region: A retrospective analysis of 105 patients

Background

Extranodal marginal zone B‐cell lymphoma of mucosa‐associated lymphoid tissue (MALT lymphoma) in the oromaxillofacial head and neck region is rare, with limited data available. This retrospective study explored the clinical features, stage, treatment, and prognosis of this disease.

Methods

Overall, 105 patients with MALT lymphomas in the oromaxillofacial head and neck region were included in this retrospective analysis. SPSS 22.0 software package was used for data analysis and a two‐tailed P value of ≤.05 was considered statistically significant. Primary endpoints of the study were the complete response (CR) rate, overall survival (OS), and progression‐free survival (PFS).

Results

About 52% of the patients had long‐term xerostomia, autoimmune diseases, or chronic parotitis and 81% had diseases involving the large salivary glands. Ann Arbor staging of the patients was as follows: stages I/II, 73 patients and stages III/IV, 32 patients. In the 97 patients followed up, CR rate after initial treatment was 80%. Tumor progression was observed in 12 patients and 14 patients died. There was a significant difference between the rate of CR in localized (87%) and disseminated (67%) lymphoma patients (P = .02). The 5‐ and 10‐year PFS of the localized lymphoma patients were both 91%, whereas those of the disseminated lymphoma patients were 83% and 65%, respectively (P = .03). The 5‐year PFS rates of the chemotherapy and non‐chemotherapy groups in the disseminated lymphoma patients were 85% and 73% (P = .04). Meanwhile, the 5‐year PFS rates of the rituximab and non‐rituximab groups in the disseminated lymphoma patients were 100% and 70% (P = .03). In multivariate analysis, MALT Lymphoma International Prognostic Index (MALT‐IPI) was an independent prognostic factor affecting OS, whereas Ann Arbor staging affected PFS.

Conclusions

This study suggests that the outcome after initial treatment of MALT lymphomas in the oromaxillofacial head and neck region is satisfactory and that this disease progresses slowly. The CR rate and PFS of localized lymphoma patients are better than those of disseminated lymphoma patients. Systemic treatment (chemotherapy or rituximab) may improve PFS in disseminated disease patients. MALT‐IPI and Ann Arbor staging are independent prognostic factors.

Prolonged follow-up on lenalidomide-based treatment for mucosa-associated lymphoid tissue lymphoma (MALT lymphoma)-Real-world data from the Medical University of Vienna

Based on results of two pilot trials, lenalidomide (LEN) was found to be active and safe as monotherapy and showed an increased response rate of 80% in combination with rituximab (R) for patients with mucosa‐associated lymphoid tissue (MALT) lymphoma. While initial results were promising, there are currently no data on long‐term outcome, and larger international phase II/III trials on LEN for indolent lymphoma lack specific subgroup analyses. Thus, we have systematically analyzed 50 patients treated with LEN‐based therapy (LEN‐monotherapy n = 16, R‐LEN n = 34) at the Medical University of Vienna 2009 to 2019 and investigated long‐term outcome and relapse patterns. At a follow‐up of more than 5 years (median 68 months), 54% of patients are free of relapse, and estimated median progression‐free survival (PFS) was 72 months (95%CI 49‐96). There was no difference in PFS according to stage of disease, i.e. localized versus disseminated disease (P = .67) and previous systemic treatment (P = .16). Interestingly, but with the caveat of the limited number of patients included in this series, primary extragastric disease had a superior PFS compared with gastric lymphoma (P = .04) and also depth of response, i.e. complete or partial response versus stable disease was associated with significantly prolonged PFS (P = .01). We documented four patients (8%) with pronounced improvement of response during follow‐up including three patients initially rated as partial remission and finally achieving complete remission at 12 to 32 months. This highlights the potential of delayed responses to LEN treatment. Estimated overall survival at 5 years was excellent at 92%. These “real‐world” data confirm long‐term activity of LEN in MALT lymphoma.

Effective management strategies for patients with marginal zone lymphoma

Marginal zone lymphoma (MZL) is an uncommon indolent lymphoma classified into subtypes based on primary site of involvement: splenic, nodal and extranodal. MZLs' relative rarity has largely precluded adoption of a standard management strategy. Here, we provide an overview of the epidemiology, clinical behavior and therapeutic approaches for each subtype. Biologic insights into lymphomagenesis have identified B-cell receptor signaling as a rational therapeutic target. Recent clinical data suggest that novel agents targeting this pathway, including the Bruton's tyrosine kinase inhibitor, ibrutinib, show significant promise in treatment of relapsed MZL. More work is needed to evaluate these agents' activity in the front-line setting, possible combination regimens and the impact of resistance to B-cell receptor-targeted agents in order to optimize therapy in 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.

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.

Gastric mucosa-associated lymphoid tissue lymphoma and Helicobacter pylori infection: a review of current diagnosis and management

Helicobacter pylori (H. pylori)-associated gastritis is one of the most common infectious diseases in the United States, China and worldwide. Gastric mucosa-associated tissue lymphoma (MALT lymphoma) is a rare mature B-cell neoplasm associated with H. pylori infection that is curable by antibiotics therapy alone. The pathological diagnosis of gastric MALT lymphoma can be reached by histological examination, immunohistochemical staining and B-cell clonality analysis. H. pylori eradication is the choice of therapy for early-stage gastric MALT lymphoma. High response rates and long-term survival have been reported in refractory and localized diseases treated with low-dose radiation therapy. Systemic chemotherapy is recommended for advanced-stage gastric MALT lymphoma and cases with large B-cell lymphoma transformation. Recent advances in the pathological diagnosis and management of gastric MALT lymphoma are reviewed in this article.

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.

Systematic review of the recent evidence for the efficacy and safety of chlorambucil in the treatment of B-cell malignancies

Emergence of new agents has deeply modified treatment options and the role of chlorambucil (CLB) in B-cell malignancies. We conducted a systematic review of prospective, randomized, controlled trials (RCTs) investigating the benefits and harms of CLB used alone or in combination with other treatment in patients suffering from chronic lymphocytic leukemia (CLL), low-grade non-Hodgkin lymphoma (NHL) or Waldenström macroglobulinemia (WM). For CLL, review of the nine RCTs showed that the main advantage of CLB is its low toxicity in comparison with purine nucleoside analogs like fludarabine in either CLL or NHL. In CLL, the major disadvantage is the very low rate of complete response, except when combining an anti-CD20 antibody. For B-cell lymphoma and WM, six RCTs were summarized. Results according to the usual criteria are presented and the role of CLB, used mostly in combination with an anti-CD20 antibody, is discussed for each indication, in particular for unfit patients.

Chemoimmunotherapy for Mucosa-Associated Lymphoid Tissue-Type Lymphoma: A Review of the Literature

BACKGROUND

Biological treatments, chemoimmunotherapy, and radiotherapy are associated with excellent disease control in both gastric and extragastric mucosa-associated lymphoid tissue (MALT) lymphomas. Systemic treatment approaches with both oral and i.v. agents are being increasingly studied, not only for patients with disseminated MALT lymphoma, but also for those with localized disease. To date, however, recommendations for the use of available systemic modalities have not been clearly defined.

MATERIALS AND METHODS

The present report reviews the current data on systemic treatment options for patients with MALT lymphoma and provides recommendations for their use in everyday practice.

RESULTS

Different chemotherapeutic agents, including anthracyclines, alkylators, and purine analogs, have been successfully tested in patients with MALT lymphoma. Reducing side effects while maintaining efficacy should be the main goal in treating these indolent lymphomas. From the data from the largest trial performed to date, the combination of chlorambucil plus rituximab (R) appears to be active as first-line treatment. Similarly, R-bendamustine also seems to be highly effective, but a longer follow-up period is needed. R-monotherapy results in lower remission rates, but seems a suitable option for less fit patients. New immunotherapeutic agents such as lenalidomide (with or without rituximab) or clarithromycin show solid activity but have not yet been validated in larger collectives.

CONCLUSION

Patients with MALT lymphoma should be treated within prospective trials to further define optimal therapeutic strategies. Systemic treatment is a reasonable option with potentially curative intent in everyday practice. Based on the efficacy and safety data from available studies, the present review provides recommendations for the use of systemic strategies.

De-escalating therapy in gastric aggressive lymphoma

The treatment of primary gastric diffuse large B-cell lymphoma (DLBCL) has changed radically over the last 10–15 years, with the abandonment of routine gastrectomy in favor of more conservative therapies. Low-level evidence suggests that consolidation radiotherapy could be avoided in patients with limited-stage DLBCL of the stomach who achieve complete remission after rituximab-CHOP combination. Small, recent prospective trials suggest that selected patients with limited-stage Helicobacter pylori (H. pylori)-positive DLBCL of the stomach and favorable prognostic factors can be managed with antibiotics alone, with excellent disease control and cure rates, keeping chemo-radiotherapy for unresponsive patients. This recommendation should equally regard patients with mucosa-associated lymphoid tissue-related or de novo DLBCL. Future studies should be focused on the establishment of reliable variables able to distinguish the best candidates for exclusive treatment with H. pylori eradication from those who need for conventional chemo-immunotherapy.

The role of Helicobacter pylori eradication in the treatment of diffuse large B-cell and marginal zone lymphomas of the stomach

PURPOSE OF REVIEW

This review is focused on the effect of Helicobacter pylori eradication with antibiotics in patients with primary gastric lymphomas of indolent and aggressive nature.

RECENT FINDINGS

Gastrointestinal lymphoma is the most common form of extranodal lymphoma, involving primarily the stomach in 60-75% of cases. The most common histological subtypes are diffuse large B-cell lymphoma (DLBCL) and marginal zone B-cell lymphoma of the mucosa-associated lymphoid tissue (MALT)-type. H. pylori infection has been implicated in the pathogenesis of gastric MALT lymphoma; its role in gastric DLBCL remains controversial. Recently, international guidelines established that patients with gastric MALT lymphoma should be treated with upfront H. pylori-eradicating antibiotic therapy and that residual microscopic or molecular disease does not need for additional antiblastic treatment. The excellent prognosis of patients with gastric DLBCL managed with conservative chemo-radiotherapy led some investigators to test H. pylori eradication as exclusive treatment in prospective trials, keeping chemo-radiotherapy for unresponsive patients. This conservative strategy was well tolerated and active in patients with limited-stage DLBCL (±MALT areas) of the stomach.

SUMMARY

H. pylori eradication is a suitable strategy as exclusive upfront treatment for both patients with MALT-type lymphomas or with DLBCL of the stomach. Additional trials are needed to elucidate related controversial issues.

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.

Marginal zone lymphomas and infectious agents

A link with infectious agents, bacteria and viruses in particular, has been reported for many lymphoma entities. Marginal zone lymphomas (extranodal, nodal and splenic forms) are frequently associated with chronic infections, with important clinical, molecular, biological, and therapeutic implications. The well-known correlation between Helicobacter pylori and gastric MALT-lymphoma, the recently reported links between Chlamydophila psittaci and ocular adnexal MALT-lymphoma and Borrelia burgdorferi and cutaneous MALT lymphoma constitute the best studied examples of lymphomagenic activity of bacteria, while the hepatitis C virus represents the most extensively investigated virus associated with marginal zone lymphomas. Biological and clinical features, therapeutic implications and future perspectives of these lymphoma-microbial associations are discussed in this review.

Addition of rituximab to chlorambucil produces superior event-free survival in the treatment of patients with extranodal marginal-zone B-cell lymphoma: 5-year analysis of the IELSG-19 Randomized Study

PURPOSE

Apart from localized gastric disease, there is no consensus on standard initial treatment of mucosa-associated lymphoid tissue lymphoma. The IELSG-19 study (Randomized Trial of Chlorambucil Versus Chlorambucil Plus Rituximab Versus Rituximab in MALT Lymphoma) was launched to compare chlorambucil alone versus chlorambucil plus rituximab in patients not previously given systemic anticancer therapy.

PATIENTS AND METHODS

Patients not responding to or not suitable for local therapy were eligible. In arm A, chlorambucil was given daily 6 mg/m(2) orally (PO) for 6 weeks. Responding patients and those with stable disease continued to be given daily chlorambucil 6 mg/m(2) PO for 14 consecutive days every 28 days for four cycles. In arm B, intravenous rituximab 375 mg/m(2) per day was added on days 1, 8, 15, 22, 56, 84, 112, and 140. After completion of the planned accrual, the protocol was amended to introduce a third arm with rituximab alone. We report the planned final analysis of the first two arms (113 patients in arm A and 114 in arm B).

RESULTS

At a median follow-up of 62 months, the 5-year event-free survival (EFS) was significantly better for the patients treated in arm B (68% v 50%; P = .002) who, despite similar overall response rates (90% v 87%), achieved a higher complete remission rate (78% v 65%; P = .025). Progression-free survival was also improved but it did not reach statistical significance (P = .057). Five-year overall survival (OS) was 89% in both arms. Both treatments were well tolerated without unexpected toxicities.

CONCLUSION

Both treatments were active; the better response rate and EFS obtained with the addition of rituximab did not translate into improved OS.

Comparative outcomes of oncologic therapy in gastric extranodal marginal zone (MALT) lymphoma: analysis of the SEER-Medicare database

BACKGROUND

Therapy for gastric marginal zone (MALT) lymphoma is largely based on single-arm trials. This observational study compared survival with radiotherapy, rituximab and combination chemoimmunotherapy in this disease.

PATIENTS AND METHODS

Gastric MALT lymphoma cases diagnosed between 1997 and 2007 were selected from the Surveillance, Epidemiology and End Results-Medicare database. Propensity score analysis and competing risk models were used to compare survival in patients with stage IE treated with radiation or chemotherapy, and in patients of all stages treated with rituximab alone or with chemoimmunotherapy.

RESULTS

Among 1134 patients, 21% underwent radiation and 24% chemotherapy as initial treatment. In the balanced cohort of 347 patients with stage IE, radiotherapy alone was associated with a better cause-specific survival [hazard ratio (HR) 0.27, P < 0.001]. Patients receiving systemic therapy had better survival if it incorporated rituximab (HR 0.53, P = 0.017). After adjustment for confounding, the outcomes of those who received rituximab alone or combination chemoimmunotherapy were not statistically different (P = 0.14).

CONCLUSIONS

In elderly patients with stage IE gastric MALT lymphoma, radiotherapy was associated with lower risk of lymphoma-related death than chemotherapy. In those requiring systemic treatment, addition of cytotoxic chemotherapy to rituximab in the first-line regimen was not associated with improved survival.

The many faces of marginal zone lymphoma

Indolent B-cell lymphomas that are supposed to derive from the marginal zone (marginal zone lymphomas [MZLs]) include 3 specific entities: extranodal marginal zone lymphoma (EMZL) or mucosa-associated lymphatic tissue (MALT) lymphoma, splenic MZL (SMZL), and nodal MZL (NMZL). The clinical and molecular characteristics are different for each entity, with some shared phenotypic and genetic features. EMZL is the most common entity, accounting for approximately 70% of all MZLs. These neoplasms can arise at virtually any extranodal site and are commonly associated with chronic antigenic stimulation either as a result of infection (eg, Helicobacter pylori in the stomach) or autoimmune disease (eg, Sjögren syndrome and salivary glands). Several chromosomal translocations were also identified in EMZL, accounting in the aggregate for approximately one-third of all cases. SMZL accounts for approximately 20% of all MZLs. Patients typically present with an enlarged spleen and involvement of abdominal lymph nodes and BM. Approximately 40%-50% of SMZLs are associated with deletions of chromosome 7q. NMZL is the less common entity, representing approximately 10% of all MZLs. Patients with NMZL, by definition, have lymph node–based disease without involvement of the spleen or extranodal sites. The molecular pathogenesis of NMZL is still unknown.

Gela histological scoring system for post-treatment biopsies of patients with gastric MALT lymphoma is feasible and reliable in routine practice

The International Extranodal Lymphoma Study Group (IELSG) promoted this study to determine the inter-observer agreement in the application of the Groupe d' Etude des Lymphomes de l' Adulte (GELA) histological scoring system for evaluating residual disease in post-treatment gastric biopsies of patients with gastric Mucosa-Associated Lymphoid Tissue (MALT) lymphoma (GML). Twenty-one patients with Helicobacter pylori -associated GML and treated with anti-H. pylori therapies were considered. A total of 154 biopsy sets from follow-up endoscopic procedures after H. pylori eradication were examined independently by seven pathologists from four European countries, following histological criteria suggested by the GELA scoring system. The overall concordance rate was 83% with a kappa value of 0·64, indicating a significant agreement among the seven observers. Most non-concordant responses clustered across the border of complete remission (CR) and probable minimal residual disease (pMRD), a distinction that does not imply critical clinical impact. Accordingly, when the analysis considered CR/pMRD as a single entity, the responses showed an overall concordance rate of 89% with kappa value of 0·83, thus indicating a high degree of inter-observer agreement. This study provides additional validation of the GELA histological grading system. This scheme can therefore be recommended in routine practice and deserves to be used in prospective clinical trials.

Second cancers and residual disease in patients treated for gastric mucosa-associated lymphoid tissue lymphoma by Helicobacter pylori eradication and followed for 10 years

BACKGROUND & AIMS

Cure of Helicobacter pylori infection induces remission in most patients with gastric mucosa-associated lymphoid tissue lymphoma (GML) that is associated with these bacteria. We determined the long-term outcomes of these patients in a prospective multicenter trial and investigated whether they developed second cancers or had histologic residual disease.

METHODS

We followed 120 patients with stage EI1 GML for a median of 122 months after H pylori eradication (range, 1-171 months). Remission was determined by histology analysis and development of second cancers was documented.

RESULTS

Of the patients, 80% (96 of 120) achieved complete remission from GML, and 80% of those (77 of 96) remained disease free. Estimated mean survival time in the Kaplan-Meier analysis was 147 months (95% confidence interval: 138-156 months). Of the patients that achieved complete remission, 17% (16 of 96) had histologic residual disease after a median of 32 months (range, 3-68 months). Disease did not progress in any of these patients, and all but 1 achieved a second complete remission (median duration, 46 months). Standardized morbidity ratios revealed a significantly higher incidence of gastric cancer (8.567; 95% confidence interval, 3.566-20.582) or non-Hodgkin lymphoma (18.621; 95% confidence interval: 8.365-41.448) in the 96 patients that achieved a complete remission, compared with the general German population.

CONCLUSIONS

Cure of H pylori infection leads to continuous complete remission in most patients with H pylori-associated GML. Patients are at risk for development of secondary cancers (ie, gastric cancer and non-Hodgkin lymphoma).

Plasmacytic differentiation in MALT lymphomas following treatment with rituximab

Mucosa-associated lymphoid tissue (MALT) lymphomas are B cell neoplasms which commonly affect the gastrointestinal (GI) tract. Gastrointestinal MALT lymphomas rarely show plasmacytic differentiation (PCD), and limited data on the potential influence of the anti-CD20 antibody rituximab (R) on PCD exist in the current literature. We have retrospectively analyzed patients with GI MALT lymphomas treated with R-containing regimens because restaging is routinely performed by repeated biopsies with pathohistological response assessment. Twenty-one patients with GI MALT lymphoma were identified to have undergone R-containing therapy. In 19 patients, the lymphoma originated in the stomach, while the colon was the primarily affected organ in two cases. Four patients received R monotherapy and 17 combinations of R with various chemotherapeutic agents. Only two patients with gastric MALT lymphoma had PCD before initiation of therapy. In 7 of 19 patients (37%) without PCD at diagnosis, restaging revealed PCD after or while on treatment with R-containing regimens. Out of these seven patients, only one patient had a complete response as opposed to 10/12 without PCD. These data suggest that R or R-containing treatment regimens may not optimally eradicate the plasma cell component and thus lead to PCD in patients with GI MALT lymphoma. In view of this, rebiopsy and histological re-assessment appear mandatory in patients failing/relapsing after R-containing regimens.

Treatment of gastric marginal zone lymphoma of MALT type

IMPORTANCE OF THE FIELD

Gastric marginal zone lymphomas of mucosa-associated lymphoid tissue (MALT type) represent approximately half of all cases of lymphomas arising in the stomach. They have been strongly associated with chronic Helicobacter pylori (H. pylori) gastritis. Treatment aimed at eradicating this infection results in lymphoma remissions in the majority of patients (approximately 80%) and this represents a unique case of anticancer treatment based on the eradication of the causing factor.

AREAS COVERED IN THIS REVIEW

The effects of H. pylori eradication in suppressing the growth of this lymphoma with particular emphasis on the long-term disease control results are presented in this review. Trials of different treatment modalities for patients not responding to antibiotics are also covered.

WHAT THE READER WILL GAIN

Understanding of the effects of H. pylori eradication on suppressing the growth of gastric MALT lymphoma. Readers will learn how to distinguish between clinical, histological and molecular remission of the lymphoma and will learn alternative treatments for patients with H. pylori-negative disease and for cases not responding to eradication.

TAKE HOME MESSAGE

Gastric MALT lymphoma has an indolent course and most patients can achieve durable disease control after only anti-H. pylori therapy. For patients not responding to antibiotics, randomized trials are needed to define the best treatment modality.

Clinical activity of bortezomib in relapsed/refractory MALT lymphomas: results of a phase II study of the International Extranodal Lymphoma Study Group (IELSG)

BACKGROUND

The nuclear factor-kappa B activation in mucosa-associated lymphoid tissue (MALT) lymphoma pathogenesis provided the rationale for the evaluation of bortezomib in this malignancy.

PATIENTS AND METHODS

Thirty-two patients with relapsed/refractory MALT lymphoma were enrolled. Thirty-one patients received bortezomib 1.3 mg/m(2) i.v., on days 1, 4, 8, and 11, for up to six 21-day cycles.

RESULTS

Median age was 63 years (range, 37-82 years). Median number of prior therapies was 2 (range, 1-4). Nine patients had Ann Arbor stage I, 7 patients had stage II, and 16 patients had stage IV. Primary lymphoma localization was the stomach in 14 patients; multiple extranodal sites were present in 10 patients. Among the 29 patients assessable for response, the overall response rate was 48% [95% confidence interval (CI) 29% to 67%], with 9 complete and 5 partial responses. Nine patients experienced stable disease and six had disease progression during therapy. The most relevant adverse events were fatigue, thrombocytopenia, neutropenia, and peripheral neuropathy. After a median follow-up of 24 months, the median duration of response was not reached yet. Five deaths were reported, in two patients due to disease progression.

CONCLUSION

Bortezomib is active in relapsed MALT lymphomas. Further investigations to identify optimal bortezomib dose, schedule, and combination regimens are needed since the frequent detection of dose-limiting peripheral neuropathy.

Long-term follow-up of gastric lymphoma after stomach conserving treatment

The therapeutic strategy in gastric lymphoma has completely changed over the last two decades. This change is mainly characterised by the abandonment of surgery in favour of conservative therapies and the introduction of Helicobacter pylori eradication therapy. It became evident that conservative treatment with radiation and/or chemotherapy is at least as effective as surgical resection and additionally offers the advantage of stomach preservation and better quality of life. The therapeutic goal is undoubtedly complete remission of the lymphoma as a necessary basis for cure of the disease. Both radiotherapy and chemotherapy have a high curative potential in gastric MALT lymphoma and diffuse large B-cell lymphoma (DLBCL), respectively. An open question is the additional benefit of radiation following Rituximab-CHOP chemotherapy in DLBCL. In patients with gastric MALT lymphoma of stage I H. pylori eradication offers complete remission rates of up to 80% with excellent long-term prognosis and a real chance of cure. Patients with MALT lymphoma of stage II and those with DLBCL of stage I may also respond to eradication therapy in the individual case. It also emerged recently that there is no need for any oncological therapy in patients revealing minimal histological residuals after successful H. pylori eradication. A watch-and-wait strategy is the adequate management of this condition. In summary, therapy of gastric lymphoma is nowadays individualised with lymphoma type, stage, and H. pylori status as the determinants of the choice of treatment. Efficacy and quality of life are strong arguments for a definite conservative approach encompassing H. pylori eradication, radiation and chemotherapy.

Role of chemotherapy in gastric MALT lymphoma, diffuse large B-cell lymphoma and other lymphomas

Primary gastrointestinal lymphomas are relatively common, with the large majority occurring in the stomach. In the commonest histological subtype, i.e. diffuse large B-cell lymphoma (DLCBL), chemotherapy has widely been applied in the past, either following surgery or - in more recent years - as part of conservative management in combination with radiotherapy. Relatively little data, however, exist for chemotherapy as sole treatment modality in localised gastric DLBCL, which nevertheless are highly promising and suggest that combination therapy might overtreat a substantial proportion of patients. In gastric MALT-lymphoma, the use of chemotherapy has been restricted either to patients with a priori disseminated disease or individuals judged to be at high risk or failing local treatment approaches. Only a few prospective phase II studies have been performed, and one controlled trial has shown that chemotherapy was superior in terms of event free survival at ten years when compared to radiation and surgery. These suggest that systemic treatment approaches might be highly effective both in gastric DLBCL as well as MALT-lymphoma, and the scope of this article is to briefly summarize current data on chemotherapy in gastric and GI-lymphomas according to histologic subtypes.