Incidence of gastric B-cell lymphomas: a population-based study in Germany

From modern pathogenetic insights and molecular understanding to new deescalating therapeutic strategies in gastric MALT-lymphoma

Based on new insights into the aetiology and pathogenesis of gastric marginal-zone B-cell lymphoma of MALT (MALT-lymphoma) and its histomorphological and molecular characteristics, important progress in our understanding of the disease and its clinical management has been made during the last decades. A landmark in this development was the identification of Helicobacter pylori as the decisive pathogenetic factor for gastric MALT lymphoma. We, here, give an overview about the history and the current knowledge of the histology, genetics, and molecular characteristics and pathogenesis of gastric MALT lymphoma. We then focus on how these findings have fundamentally changed its clinical management over the last three decades with consequent deescalating therapeutic strategies.

Emerging Roles for the Gut Microbiome in Lymphoid Neoplasms

Lymphoid neoplasms encompass a heterogeneous group of malignancies with a predilection for immunocompromised individuals, and the disease burden of lymphoid neoplasms has been rising globally over the last decade. At the same time, mounting studies delineated a crucial role of the gut microbiome in the aetiopathogenesis of various diseases. Orchestrated interactions between myriad microorganisms and the gastrointestinal mucosa establish a defensive barrier for a range of physiological processes, especially immunity and metabolism. These findings provide new perspectives to harness our knowledge of the gut microbiota for preclinical and clinical studies of lymphoma. Here, we review recent findings that support a role for the gut microbiota in the development of lymphoid neoplasms and pinpoint relevant molecular mechanisms. Accordingly, we propose the microbiota-gut-lymphoma axis as a promising target for clinical translation, including auxiliary diagnosis, novel prevention and treatment strategies, and predicting clinical outcomes and treatment-related adverse effects of the disease in the future. This review will reveal a fascinating avenue of research in the microbiota-mediated lymphoma field.

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.

Gastric MALT lymphoma in a population-based study in France: clinical features, treatments and survival

BACKGROUND

Gastric mucosa-associated lymphoid tissue (MALT) lymphoma is a rare disease, and most available data on gastric MALT lymphoma (GML) come from clinical studies of selected patients treated in centres of excellence.

AIMS

To analyse the clinical features, management and survival of GML patients in a population-based study in France METHODS: All new cases of GML diagnosed between 2002 and 2010 in 11 French areas covered by cancer registries were included. Pathology reports were verified and, if necessary, reviewed by an expert pathologist. All clinical data were retrospectively collected from medical files and analysed using stata V. 14 software.

RESULTS

Four hundred and sixteen patients with confirmed GML (50% male, median age 67 years) were identified. Among them, 44 showed an early transformation into diffuse large B cell lymphoma and were considered to have had an initially missed high-grade lymphoma. At diagnosis, 76% of patients were at stage IE/II, and 24% at stage III/IV of the disease. Helicobacter pylori infection was found in 57% of the patients. Eradication treatment was administered to 76% of patients and complete remission (CR) was obtained in 39%. One hundred and ninety patients received at least one other treatment, including 10 already in CR after eradication. Altogether, CR was obtained in 70% of patients and the 5-year overall survival was 79% (95% CI [75-83]).

CONCLUSIONS

In comparison to clinical series, in the general population, GMLs are more frequently diagnosed at an advanced stage, their clinical management is heterogeneous, and there is a risk of misdiagnosis and overtreatment. These results highlight the necessity of following currently available guidelines in this field.

Deregulation of miRNA in Helicobacter pylori-Induced Gastric MALT Lymphoma: From Mice to Human

Gastric MALT lymphoma (GML) is directly caused by Helicobacter pylori infection but occurs only in a small number of infected subjects. Mechanisms underlying the initiation and progression of GML remain unclear. MicroRNAs (miRNAs) are small non-coding RNAs that are now considered as major players in inflammation and carcinogenesis, acting as oncogenes or tumor suppressors. Previous laboratory studies have shown in a GML mouse model that overexpression of a distinct set of five miRNAs (miR-21a, miR-135b, miR-142a, miR-150, miR-155) could play a critical role in the pathogenesis of GML. Our goal was to compare the miRNA expression profile obtained in the GML mouse model to that in human GML (11 cases of GML compared to 17 cases of gastritis control population). RTqPCR on the five dysregulated miRNAs in the GML mouse model and PCR array followed by RTqPCR confirmation showed that four miRNAs were up-regulated (miR-150, miR-155, miR-196a, miR-138) and two miRNAs down-regulated (miR-153, miR-7) in the stomachs of GML patients vs. gastritis control population. The analysis of their validated targets allowed us to postulate that these miRNAs (except miR-138) could act synergistically in a common signaling cascade promoting lymphomagenesis and could be involved in the pathogenesis of GML.

Gastric MALT lymphoma and Helicobacter pylori

Marginal zone lymphomas of the MALT type are a type of B-cell neoplasms that involve extranodal tissues and have an indolent clinical behaviour. The stomach is the most common site and most patients are infected by Helicobacter pylori. An increase in the resistance of this bacterium to several antibiotics has been observed in the last years and this fact has determined the review of treatment guidelines. In areas with resistance to clarithromycin greater than 15%, classical triple therapy should be abandoned and quadruple regimens with or without bismuth are currently recommended. Thus, these new guidelines for eradication treatment should be applied to patients with gastric MALT lymphoma associated with H. pylori infection.

Increased risk for metachronous gastric adenocarcinoma following gastric MALT lymphoma-A US population-based study

BACKGROUND

Gastric mucosa-associated lymphoid tissue lymphoma (gMALT) and gastric adenocarcinoma (GC) are long-term complications of chronic Helicobacter pylori (HP) gastritis. Treatment of HP infection induces remission in most patients with gMALT. Endoscopic follow-up is not currently endorsed after complete remission. However, the risk of GC in these patients is unclear.

OBJECTIVE

The objective of this study is to estimate GC risk in gMALT patients.

METHODS

The National Cancer Institute Surveillance, Epidemiology and End Results 13 (SEER) database-Nov 2014 Sub (1992-2012) was used to identify adult patients diagnosed with gMALT between 1992 and 2012. The standardized incidence ratio of second primary GC after a latency period of 12 months was calculated and compared to a reference SEER cohort of identical age, sex and time period. The risk of GC in these patients was also stratified by latency period (five years) and age.

RESULTS

We identified 2195 cases of gMALT lymphoma, and 20 (0.91%) of them subsequently developed GC with a relative risk (RR) of 4.32 (95% CI 2.64-6.67) compared to the American population. The median latency time was five years and the risk was maintained afterward (RR 4.92, 95% CI 2.45-8.79). When stratified by age group the risk was highest for the 45-64 group (RR 14.04, 95% CI 5.64-28.93).

CONCLUSION

gMALT lymphoma is associated with an increased risk of metachronous gastric adenocarcinoma. The risk is still present after more than five years of follow-up. Further studies may clarify the most adequate follow-up strategy.

Role of follow-up endoscopic examination in treatment response assessment for patients with gastric diffuse large B cell lymphoma

OBJECTIVE

According to lymphoma guidelines, gastric diffuse large B cell lymphoma (DLBCL) patients should undergo regular computed tomography (CT) and/or positron emission tomography (PET) examinations to assess treatment response. Endoscopic examinations are not indicated in the guidelines. The aim of this study was to investigate the utility of endoscopic examinations during and after treatment for DLBCL.

METHODS

We reviewed the patients diagnosed with gastric DLBCL at Seoul St. Mary's Hospital. All patients underwent endoscopy and radiologic examinations at every follow-up appointment. Radiologic response was defined according to World Health Organization criteria and endoscopic response was determined based on the Groupe d'Etude des Lymphomes de l'Adult grading system that is widely used in post-treatment evaluation of gastric MALT lymphoma.

RESULTS

Forty-five patients were analyzed. Within a median follow-up period of 34 months, 35 patients achieved both radiologic and endoscopic complete remission (CR). The median times to endoscopic and radiologic CR were not significantly different (21 versus 16 weeks, p = 0.118). However, in 25 patients with stage I disease, endoscopic CR [median (range), 20 (11-36)] was achieved later than radiologic CR [median (range), 13 (8-36)] (p = 0.027). Among 40 patients who achieved radiologic CR, 35 patients who also achieved endoscopic CR maintained remission during the follow-up. Two of the five patients who achieved radiologic CR without endoscopic CR experienced recurrence.

CONCLUSIONS

In gastric DLBCL patients, endoscopic response does not always correlate with radiologic response and might predict disease recurrence. We suggest that follow-up endoscopic examination with biopsy should be performed in addition to radiologic examination.

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.

Neonatal thymectomy favors Helicobacter pylori-promoted gastric mucosa-associated lymphoid tissue lymphoma lesions in BALB/c mice

Neonatal thymectomy in BALB/c mice has been described as a model of gastric mucosa-associated lymphoid tissue (MALT) lymphoma (GML). By using this experimental system, we screened, for the first time to our knowledge, Helicobacter pylori GML-associated strains for their capacity to promote disease. A cohort of BALB/c mice underwent thymectomy at day 3 after birth (d3Tx). Successful thymic ablation was evaluated by the degree of lymphopenia in blood samples collected at 4 weeks of age. d3Tx and non-thymectomized controls were infected with either GML strains (B38 or B47) or control strains (SS1 or TN2GF4). Gastric samples collected at 6, 12, and 18 months after infection were studied for bacteria content, and submitted to histological, immunochemical, molecular, and immunological analyses. Severe gastric inflammation was only observed in d3Tx mice. In these animals, the gastric lamina propria was infiltrated with lymphoid cells organized in follicles composed of B cells with few infiltrating T cells. PCR of D/J IgH gene segments proved the monoclonality of infiltrating B cells, which strongly correlated with the presence of lymphoepithelial lesions. B-cell infiltrates were particularly prominent in mice infected with the B47-GML strain. No pathological changes were detected in noninfected d3Tx mice. We identified new H. pylori isolates adapted to the mouse stomach with high potential of GML development, which is only revealed in hosts rendered lymphopenic by neonatal thymic ablation.

[Gastric MALT-type lymphoma. Pathology, pathogenesis, diagnostics and therapy]

Helicobacter pylori infection plays a central role in the development of gastric MALT-type (mucosa-associated lymphoid tissue) lymphoma. Infection results in chronic H. pylori gastritis and stimulates together with antigens or autoantigens proliferation of B-lymphocytes which is the basis for the neoplastic transformation. Histology of MALT-type lymphoma is architecturally similar to the physiological MALT. Invasion and destruction of the gastric epithelium with development of so-called lympho-epithelial lesions is the most important diagnostic criterion. Cytologically MALT-lymphoma resembles centrocytes and monocytes. For definitive lymphoma diagnosis and for the differential diagnosis from other small cell lymphomas in the stomach immunohistochemistry can be helpful. The phenotype of MALT-type lymphoma is identical to non-neoplastic B-lymphocytes of the marginal zone (CD20+, CD5-, CD10- and CD23-). Individual therapy is strongly dependent from histological type and lymphoma stadium. Therapy modalities are H. pylori eradication, radiochemotherapy, surgery or a combination of these. Aim of the therapy is the complete lymphoma regression and cure of the disease.

Diagnosis and staging in gastrointestinal lymphoma

The diagnosis gastrointestinal lymphoma can be made on endoscopic biopsies in the vast majority of cases. Definitive subtyping of the lymphoma according to the WHO classification with the use of additional immunological and molecular markers is the cornerstone for further decision making. Several lymphomas may occur multifocally or show both small cell and large cell components. Therefore, a second endoscopy with an extensive biopsy protocol (mapping) may be mandatory. Staging procedures are required for therapeutic decision making and should include CT-scan, laboratory studies and bone marrow examination as required in other lymphomas. Additional studies must be performed depending subtype and localisation of the lymphoma. In gastric lymphoma endosonography reveals prognostic information. In marginal zone lymphoma of MALT-type attention to other MALT-sites and autoimmune diseases is necessary. In enteropathy-associated T-cell lymphoma screening for coeliac disease and enteroscopy are required. In several lymphomas (diffuse large B-cell lymphoma and mantle cell lymphoma) a PET-scan is considered as standard of care. The value of staging procedures after treatment is less well defined. At least in gastric lymphomas, histology is the gold standard after treatment and during follow-up.

Incidence and survival of gastric non-Hodgkin's lymphoma: a population-based study from the Association of the French Cancer Registries (FRANCIM)

BACKGROUND

Most epidemiological studies on gastric lymphomas (GL) were carried out before changes in therapy were introduced. The aim of the study was to measure the incidence of GL and to estimate survival.

MATERIAL AND METHODS

Data were provided by the Association of the French Cancer Registries database. Age-standardized incidence rates were calculated for 786 incident cases diagnosed between 1978 and 2002. Crude and relative survival were calculated for 361 cases diagnosed between 1989 and 1997. Effects specific to sex, age at diagnosis, year of diagnosis, and grade of malignancy were estimated in multivariate analysis.

RESULTS

Incidence was stable during the study period. However, high-grade GL frequency increased whereas low-grade and not otherwise specified (NOS) GL frequencies were respectively stable and decreased. At 5 years, relative survival was 63% in men and 60% in women. Patients aged 75 or older had a five-year relative survival of 33%. Age at diagnosis was the only significant prognostic factor in multivariate analysis. Time trend improvement in prognosis was observed.

DISCUSSION

Results in elderly patients show that therapeutic regimens should be specifically designed and assessed for them. The prognosis improvement trend is probably related to the implementation of changes in management of patients and has to be confirmed by more recent data.

Gastric MALT lymphoma: epidemiology and high adenocarcinoma risk in a nation-wide study

BACKGROUND

Gastric marginal zone non-Hodgkin lymphomas MALT type (gMALT) and gastric adenocarcinomas (GC) are long-term complications of chronic Helicobacter pylori gastritis, however, the incidence of gMALT and the GC risk in these patients is unclear.

OBJECTIVE

To evaluate epidemiological time trends of gMALT in the Netherlands and to estimate GC risk.

METHODS

Patients with a first diagnosis of gMALT between 1991 and 2006 were identified in the Dutch nation-wide histopathology registry (PALGA). Age-standardised incidence rates were calculated. The incidences of GC in patients with gMALT and in the Dutch population were compared. Relative risks were calculated by a Poisson Model.

RESULTS

In total, 1419 patients were newly diagnosed with gMALT, compatible with an incidence of 0.41/100,000/year. GC was diagnosed in 34 (2.4%) patients of the cohort. Patients with gMALT had a sixfold increased risk for GC in comparison with the general population (p<0.001). This risk was 16.6 times higher in gMALT patients aged between 45 and 59 years than in the Dutch population (p<0.001).

CONCLUSIONS

GC risk in patients with gMALT is six times higher than in the Dutch population and warrants accurate re-evaluation after diagnosis and treatment for gMALT.

Primary extranodal lymphomas of stomach: clinical presentation, diagnostic pitfalls and management

Gastrointestinal lymphoma is the most common form of extranodal lymphoma, accounting for 30%-40% of cases. The most commonly involved site is the stomach (60%-75% of cases), followed by the small bowel, ileum, cecum, colon and rectum. 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). Helicobacter pylori infection has been implicated in the pathogenesis of MALT gastric lymphoma, but its role in gastric diffuse large B-cell non-Hodgkin's lymphoma (NHL) is controversial. The therapeutic approach for patients with gastric NHL has been revised over the last 10 years. Conservative treatment with anthracycline-based chemotherapy alone or in combination with involved-field radiotherapy has replaced gastrectomy as standard therapy in cases with DLBCL. Additionally, MALT lymphomas are mainly treated with antibiotics alone, which can induce lasting remissions in those cases associated with H. pylori infection. Nevertheless, various therapeutic aspects for primary gastric lymphomas are still controversial and several questions remain unanswered. Among others, the role of rituximab, consolidation radiotherapy as well as H. pylori eradication in histological aggressive subtypes warrants better clarification.

Germline variations of the topoisomerase IIα gene as risk factors for primary gastric B-cell lymphoma

We investigated if germline variations of the Topoisomerase II alpha gene could predispose patients with chronic Helicobacter pylori infection to develop gastric lymphoma and conducted a mutation detection of the entire promoter region. Single marker and haplotype analysis did not reveal any associations with development of gastric lymphoma in general, histological grade or stage of disease (P>0.05). No genetic variations in the promotor region were found in 92 chromosomes of lymphoma patients and controls and linkage disequilibrium indicated a highly conserved genomic region. The results of our work exclude genetic variations as predisposing factors of primary gastric B-cell lymphoma development.

Treatment of gastric mucosa-associated lymphoid tissue lymphoma: Helicobacter pylori eradication and beyond

Gastric mucosa-associated lymphoid tissue (MALT) lymphoma is the paradigm of lymphomas developing in extranodal areas after antigen stimulation. In the stomach, Helicobacter pylori colonization induces the appearance of MALT and, eventually, MALT-derived lymphoma. This type of lymphoma is initially a localized form of disease, but may disseminate and transform into high-grade lymphoma, making full staging (as for nodal lymphomas) and endoscopic ultrasonography to evaluate the penetration of the lymphoma through the gastric wall mandatory. In localized gastric MALT lymphoma, the first step in treatment is eradication of H. pylori, which results in 60-90% regression. This response is maintained for years in most patients, with only 10-15% relapse, frequently precipitated by H. pylori reinfection. A component of high-grade lymphoma, penetration to gastric serosa or beyond and translocation t(11;18) are the main factors that make lymphoma resistant to eradication. Surgery or radiotherapy can cure localized lymphomas in 75-90% of patients. Chemotherapy with alkylating agents, combination chemotherapy and purine analogs, and anti-CD20 antibodies can also induce remission of localized lymphomas refractory to eradication, as well as locally advanced and disseminated lymphomas. The optimum chemotherapy treatment for advanced disease has not yet been established; however, combination therapy, including purine analogs with or without anti-CD20, may be a promising option. Despite histological responses and prolonged remissions, residual molecular disease can be demonstrated in most cases treated with H. pylori eradication, radiotherapy or alkylating agents, and even after more intense chemotherapy, although this does not seem to lead to late relapses. High-grade gastric MALT lymphoma should be treated with chemotherapy, with cyclophosphamide, doxorubicin, oncovin and prednisone being the best first-line option. All gastric MALT lymphomas associated with H. pylori should receive eradication treatment in addition to other required treatment.

Illness experience before and after an initiative to identify, treat, and prevent Helicobacter pylori-related diseases in the workplace

Objective outcome measures are needed to confirm the merits of large-scale health initiatives in the workplace. We used aggregate medical claims data to evaluate the illness experience of 5160 employees during the 2 years after versus the 2 years before an intervention intended to identify, treat, and prevent Helicobacter pylori-related illnesses. Across all participants, a 2.1-fold reduction (95% confidence interval 1.4-3.1) in ulcer-related illness episodes and a marginal 1.1-fold reduction (95% confidence interval 0.9-1.4) in episodes due to other stomach and duodenal diseases were achieved. Improvement in claims experience was most notable among 250 employees with ulcer findings on the screening examination. This H. pylori health initiative appears to have contributed to a cost-effective reduction in subsequent illness episodes due to ulcer and possibly due to other stomach and duodenal disease.

Helicobacter pylori and gastric malignancies

Despite decreasing incidence during the last 50 years, gastric cancer still ranks as one of the most frequent cancers. A multifactorial model of human gastric carcinogenesis is currently accepted in which different dietary and nondietary factors, including genetic susceptibility of the host and Helicobacter pylori infection are involved at different stages in the cancer process. On the molecular level, at least two phenotypes, associated with distinct pathways of genome destabilization, have been identified. However, applying new technologies such as cDNA microarrays a new era in the analysis of molecular markers has started. This molecular technology may open the path towards novel treatment modalities, i.e. gene therapy. Epidemiological, biological, and molecular genetic studies have also implicated the role of H. pylori in lymphomagenesis. Knowledge of pathogenesis and therapy is increasing while good epidemiological data are rare. Many studies have demonstrated that MALT-type lymphomas develop along two different pathways: t(11;18)-positive cases, and t(11;18)-negative cases. Meanwhile, a third translocation could be detected, the t(14;18), opening the discussion of a possible third pathway of lymphoma development.

Helicobacter pylori and carcinogenesis of gastric B-cell lymphomas

Primary non-Hodgkin's lymphomas of the stomach are associated with Helicobacter pylori infection. We analyzed gastric lymphoma onset data with respect to prior H. pylori infections based on the multistage theory of carcinogenesis. This theory provides a link between epidemiological data and biological processes. The study involved 133 patients, aged 29-75 years, diagnosed with marginal zone B-cell lymphoma (MZBL) and diffuse large cell B-cell lymphoma (DLBL). A 2-parametric Weibull model was applied to MZBL and DLBL onset data. Median age of diagnosis of MZBL (DLBL) was 59 years (55 years) in males and 65.5 years (64 years) in females. Infection with H. pylori was found in 81.3% (59.5%) of the patients diagnosed with MZBL (DLBL). Lymphoma latency data were fitted to Weibull distributions with a shape parameter of 5.7 for MZBL cases and 4.2 for DLBL. The shape parameter that indicates the number of steps in carcinogenesis was approximately independent of the status of infection with H. pylori in DLBL in contrast to MZBL. It was shown that gastric lymphoma onset data can be described by Weibull distribution functions. The findings support the hypothesis that MZBL and DLBL have different lines of development. There is indication of stronger antigen dependency in the carcinogenesis of MZBL in comparison to DLBL.