Early stage gastric MALT lymphoma with high-grade component cured by Helicobacter pylori eradication

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

BACKGROUND

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

AIM

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

METHODS

Bibliographical searches were performed in MEDLINE up to June 2011.

RESULTS

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

CONCLUSIONS

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

Infectious agents and lymphoma

In the past 25 years revelations on the genesis of human cancer have come at an increasing pace. Research on oncogenic infectious agents, especially viruses, has helped us to understand the process of malignant transformation of cells because the cellular events in viral-driven transformation mirror, often brilliantly, basic cellular processes that culminate in cancer, even those not associated with viruses. Infectious agents, especially viruses, account for several of the most common malignancies-up to 20% of all cancers. Some of these cancers are endemic, with a high incidence in certain geographic locations, but sporadic/lower incidence in other parts of the world. Lymphomas arise frequently in association with infectious agents such as Epstein-Barr virus, human immunodeficiency virus, human herpes virus 8, Helicobacter pylori, and hepatitis C virus. In this review, we will focus on the association between infectious agents and lymphomas, with a look at the molecular mechanisms they use to disturb cell regulation and eventually result in cancer.

Presence of a high-grade component in gastric mucosa-associated lymphoid tissue (MALT) lymphoma is not associated with an adverse prognosis

Gastric mucosa-associated lymphoid tissue (MALT) lymphoma and diffuse large B cell lymphoma (DLBCL) show a spectrum of disease characterized by varying proportions of low-grade and high-grade components. While the natural history and optimum treatment for low-grade gastric MALT lymphoma and DLBCL is well established, the prognosis and optimal treatment of patients with both low- and high-grade components is not well established. The purpose of our study was to evaluate the clinical characteristics, survival outcomes, and prognostic factors of patients with gastric MALT lymphoma and gastric DLBCL. A retrospective review of patients with gastric MALT lymphoma, gastric DLBCL, or MALT lymphoma with a high-grade component treated at our centers from 1994 to 2006 was performed. Patients were divided into three categories: "pure MALT lymphoma," "MALT lymphoma with high-grade component" (mixed), and "pure DLBCL." Seventy-six patients were included in our study-26 with pure MALT, 22 with MALT with high-grade component ("mixed"), and 28 with pure DLBCL. Pure MALT lymphoma and mixed lymphoma patients had similar clinical characteristics, whereas pure DLBCL patients had less favorable disease characteristics with significantly poorer performance status, higher number of extranodal sites of disease, higher stage, and larger proportion of bone marrow involvement and international prognostic index (IPI) scores compared with mixed lymphoma. The majority of mixed lymphoma (72.7%) and DLBCL patients (71.4%) were treated with chemotherapy. Of patients receiving chemotherapy, a higher proportion of mixed lymphoma and DLBCL patients received anthracycline-based combination chemotherapy regimens compared with MALT lymphoma (73% vs 71% vs 8%) whereas the proportion of mixed lymphoma and DLBCL patients was similar (p = 0.919). At a median follow-up of 37 months, the 5-year overall survival was 66.9%. The 5-year overall survival was 78% for MALT lymphoma, 84% for mixed lymphoma, and 45% for DLBCL. On univariate analysis, DLBCL histology, age, performance status, serum albumin, lactate dehydrogenase, bone marrow, number of extranodal sites, stage, and IPI score were prognostic for inferior survival. On multivariate analysis, DLBCL histology remained significantly prognostic for inferior survival, independent of chemotherapy regimen (hazard ratio (HR) 6.66, 95% confidence interval (CI) 2.01-21.41, p = 0.001). Mixed histology was not prognostic for inferior survival (HR 1.13, 95% CI 0.28-4.54, p = 0.868). Other factors prognostic for inferior survival were serum albumin <37 g/L (HR 3.22, 95% CI 1.11-13.22, p = 0.034) and treatment with non-cyclophosphamide, doxorubicin, vincristine, and prednisolone chemotherapy (HR 4.89, 95% CI 1.67-14.36, p = 0.004). In conclusion, the clinical characteristics of mixed histology MALT lymphoma are similar to low-grade MALT lymphoma and significantly different from pure DLBCL. The prognosis of mixed histology MALT lymphoma is significantly better than pure DLBCL, independent of IPI and chemotherapy regimen, and pure DLBCL histology is independently prognostic of inferior survival outcome.

High grade B-cell gastric lymphoma with complete pathologic remission after eradication of Helicobacter pylori infection: report of a case and review of the literature

Background

Treatment of primary gastric diffuse large B-cell lymphoma is still controversial. The treatment of localized disease was based on surgery alone, or followed by chemotherapy and/or radiotherapy. High-grade gastric lymphomas are generally believed to be Helicobacter pylori (HP)-independent growing tumors. However a few cases of regression of high-grade gastric lymphomas after the cure of Helicobacter pylori infection had been described.

Case presentation

We report here a case with primary diffuse large B-cell lymphoma that showed a complete pathologic remission after HP eradication and we reviewed the literature. A computerized literature reach through Medline, Cancerlit and Embase were performed, applying the words: high grade gastric lymphoma, or diffuse large B cell, MALT gastric lymphoma, DLBCLL (MALT) lymphoma and Helicobacter. Articles and abstracts were also identified by back-referencing from original and relevant papers. Selected for the present review were papers published in English before January 2007.

Conclusion

Forty two cases of primary high grade gastric lymphoma that regressed with anti HP treatment were found. There were anedoctal cases reported and patients belonging to prospective studies; four trials studied the effect of eradication of Helicobacter pylori as first line therapy in high grade gastric lymphoma: 22 of a total of 38 enrolled patients obtained complete remission. Depth of gastric wall infiltration and clinical stage were important factors to predict the response to antibiotic therapy. Our case and the review of the literature show that high-grade transformation is not necessarily associated with the loss HP dependence. In early stage, for high-grade B-cell HP-positive gastric lymphomas, given the limited toxicity of anti-HP therapy, this treatment may be considered as one of the first line treatment options.

Long-term results of anti-Helicobacter pylori therapy in early-stage gastric high-grade transformed MALT lymphoma

BACKGROUND

Several independent clinical studies have reported that Helicobacter pylori eradication therapy could achieve complete remission in some patients with H. pylori-positive early-stage gastric mucosa-associated lymphoid tissue (MALT) lymphoma.

METHODS

To compare the long-term results of anti-H. pylori therapy in early-stage, gastric low-grade and high-grade transformed MALT lymphoma, two multicenter prospective studies of anti-H. pylori therapy for early-stage gastric lymphoma conducted in Taiwan, one for low-grade MALT lymphoma, with 34 patients enrolled from March 1996 through April 1999, and one for high-grade transformed tumors (diffuse large B-cell lymphoma with features of MALT, DLBCL[MALT] lymphoma), with 24 patients enrolled since June 1995, were directly compared. In both studies, patients generally received 2 weeks of antibiotics and had multiple sequential follow-up endoscopic examinations until complete histologic remission (CR) or disease progression; patients were monitored through January 31, 2004. CR was defined as regression of lymphoid infiltration to Wotherspoon's score of 2 or less on all pathologic sections of endoscopic biopsy specimens. All statistical tests were two-sided.

RESULTS

The H. pylori-positive rate among the 34 low-grade patients was 94% (32 of 34). All 24 selected high-grade patients were H. pylori positive. H. pylori was eradicated in 97% (30 of 31) of evaluable H. pylori-positive low-grade patients and in 92% (22 of 24) of high-grade patients, which led to CR in 80% (24 of 30, 95% confidence interval [CI] = 65% to 95%) and 64% (14 of 22, 95% CI = 42% to 86%) of patients, respectively. None of the five patients who were either initially H. pylori negative or had persistent H. pylori infection after antibiotics achieved CR. After median follow-up of more than 5 years in complete responders, tumor recurrence was observed in three (13%) low-grade patients but not in high-grade patients.

CONCLUSIONS

Anti-H. pylori therapy may be considered as one of the treatment options for early-stage H. pylori-positive gastric DLBCL(MALT), and large-scale prospective studies to validate its use as first-line therapy for such tumors should be undertaken.

Clinicopathologic study of mucosa-associated lymphoid tissue lymphoma in gastroscopic biopsy

AIM: To explore and discuss the clinicopathologic characteristics of mucosa-associated lymphoid tissue (MALT) lymphoma in gastroscopic biopsy specimen.

METHODS: A retrospective study of 26 cases of lymphoma diagnosed by gastroscopic biopsy during 1999 to 2001 from gastroscopy files of Xijing Hospital was made. The diagnostic criteria were adopted according to the new classification of non-Hodgkin's lymphoma.

RESULTS: Twenty-six cases of primary gastric lymphoma consisting of 15 men and 11 women, aged between 23 to 76 years were recruited from 6225 cases who received gastroscopy. All of them were diagnosed by both endoscopic findings and histological examinations. Histologically, 23 cases were MALToma (low grade) and 3 cases lymphoblastic lymphoma (high grade). Immunohistochemically, all cases were CD20 positive, while CK and EMA were negative.

CONCLUSION: The majority of the cases of primary low-grade gastric lymphoma have morphologic and clinical features that justify their inclusion in the category of low-grade lymphoma of mucosa associated lymphoid tissue.

Gastric lymphoma: the revolution of the past decade

BACKGROUND

Gastric MALT type lymphomas are distinct lymphomas that may develop after chronic antigenic stimulation caused by infection with Helicobacter pylori. An early antigen-dependent phase precedes the development of an antigen-independent phase.

METHODS

Narrative review.

RESULTS

The causative relationship between a chronic H. pylori infection and gastric MALT lymphomas has been based on epidemiological, histological, experimental and therapeutic studies. H. pylori eradication leads to a histological remission in +/- 70% of patients in early stage low-grade MALT lymphoma. There is no basis for therapeutic consequences in the case of persistent monoclonality. Full thickness invasion of the gastric wall and lymph node involvement and/or high-grade lymphoma denote the transition to an antigen-independent phase and calls for conventional treatment modalities. Molecular findings show a specific translocation in low-grade MALT lymphomas: t(11,18) and nuclear expression of bcl-10 that are highly indicative of the transition of the antigen-dependent into the antigen-independent phase. Other chromosomal and molecular findings are probably also involved.

CONCLUSION

The multistep pathogenesis of chronic H. pylori gastritis into low-grade gastric MALT lymphoma and tumour progression to a higher stage and grade are characterized by multiple molecular biological events. Antigen-dependency during the early phase of this malignancy is proven by the results of H. pylori eradication.

Long-term follow-up of gastric MALT lymphoma after H. pylori eradication

For almost 10 years, we have been familiar with the concept of mucosa-associated lymphoid tissue (MALT)-type lymphoma of the stomach caused by chronic Helicobacter pylori infection. Many epidemiologic, biologic, and molecular genetic studies have implicated H. pylori for its role in lymphoma genesis. Since the first reports on complete remission of gastric MALT lymphomas after cure of bacterial infection, many clinical studies have investigated the effect of eradicating H. pylori on the course of MALT lymphoma, and indeed were able to confirm remission of the lymphoma. To date, more than 650 patients worldwide have been treated for gastric MALT lymphoma with antibiotics, and we have gained many new insights concerning the biologic behavior of this disease, especially from the deepened knowledge of cytogenetics. Furthermore, factors relevant for the prediction of treatment outcome have been identified, which has helped to stratify patients into risk groups.

Prospective study of Helicobacter pylori eradication therapy in stage I(E) high-grade mucosa-associated lymphoid tissue lymphoma of the stomach

PURPOSE

High-grade mucosa-associated lymphoid tissue (MALT) lymphomas of the stomach are generally believed to be Helicobacter pylori-independent, autonomously growing tumors. However, anecdotal cases of regression of high-grade lymphomas after the cure of H pylori infection had been described. The present prospective study was conducted to evaluate the effect of anti-H pylori therapy in stage I(E) high-grade gastric MALT lymphomas.

PATIENTS AND METHODS

Sixteen patients with H pylori infection and stage I(E) gastric high-grade MALT lymphoma consented to a brief antibiotic therapy as first-line treatment from June 1995 through April 2000. Then, patients underwent intensive endoscopic follow-up examinations (+/- endoscopic ultrasonography) with biopsy to evaluate tumor response. Patients with significant improvement of gross lesions that accompanied regression of large cells were followed up without additional treatment. Patients without significant improvement were immediately referred to systemic chemotherapy.

RESULTS

Eradication of H pylori was achieved in 15 patients and was accompanied by rapid gross tumor regression and disappearance of large cells in 10. All 10 of these patients with early response had subsequent complete histologic remission of lymphoma. The complete remission rate was 62.5% (95% confidence interval, 35.8% to 89.1%). The response rate was not affected by the tumor grading (proportion of large blast cells within the tumor) but was adversely affected by the depth of tumor invasion. At a median follow-up of 43.5 months (range, 21.1 to 67.4 months), all 10 of these patients remained lymphoma-free. The median duration of complete response was 31.2 months (range, 14.4 to 49.1 months).

CONCLUSION

These results suggest that high-grade transformation is not necessarily associated with the loss of H pylori dependence in early-stage MALT lymphomas of the stomach.