Prospective study of Helicobacter pylori infection in primary gastric lymphoma

Helicobacter pylori infection in gastric mucosa-associated lymphoid tissue lymphoma

Gastrointestinal lymphoma is the most common type of extranodal lymphoma, and most commonly affects the stomach. Marginal zone B-cell lymphoma of the mucosa-associated lymphoid tissue (MALT) and diffuse large B-cell lymphoma are the most common histologic types of gastric lymphoma. Despite its increasing incidence, diagnosis of gastric lymphoma is difficult at an earlier stage due to its nonspecific symptoms and endoscopic findings, and, thus, a high index of suspicion, and multiple, deep, repeated biopsies at abnormally and normally appearing sites in the stomach are needed. In addition, testing for Helicobacter pylori (H. pylori) infection and endoscopic ultrasonography to determine the depth of tumor invasion and involvement of regional lymph nodes is essential for predicting response to H. pylori eradication and for assessment of disease progression. In addition, H. pylori infection and MALT lymphoma development are associated, and complete regression of low-grade MALT lymphomas after H. pylori eradication has been demonstrated. Radiotherapy and/or chemotherapy can be used in cases that show poor response to H. pylori eradication, negativity for H. pylori infection, or high-grade lymphoma.

[Helicobacter pylori eradication for stage I(E₁) gastric mucosa-associated lymphoid tissue lymphoma: predictive factors of complete remission]

BACKGROUND/AIMS

Eradication of Helicobacter pylori (H. pylori) is accepted as initial treatment of stage I(E₁) gastric mucosa associated lymphoid tissue (MALT) lymphoma. However, 10-20% of gastric low grade MALT lymphomas are unresponsive to H. pylori eradication treatment. The aim of this study was to find out the predictive factors of complete remission of gastric MALT lymphoma after H. pylori eradication.

METHODS

From 1995 to 2006, consecutive 95 patients with modified Ann Arbor stage I(E₁) gastric MALT lymphoma were enrolled, and their medical records were reviewed. The patients were initially treated by H. pylori eradication. The complete remission was determined by endoscopic and histologic finding.

RESULTS

Eighty eight patients (92.6%) achieved complete remission after H. pylori eradication therapy. Mean follow up time for these patients was 40+/-25 months. Seven patients (7.4%) failed to achieve complete remission. There was no significant difference in the age, sex, endoscopic appearance, and large cell component between the remission group and failure group. Among 66 patients with distal tumor, 65 patients (98.5%) achieved complete remission. On the other hand, among 13 patient with proximal tumor, 9 patients (69.2%) achieved complete remission (p=0.001). The odds ratio of proximal tumor for H. pylori eradication failure was 28.9 (95% CI=2.9-288.0).

CONCLUSIONS

The proximally location of MALT lymphoma is a risk factor of the H. pylori eradication treatment failure. Therefore, the proximally located gastric MALT lymphoma should be carefully treated and followed.

Clinicopathologic and immunohistochemical study of surgically treated primary gastric MALT lymphoma

BACKGROUND AND OBJECTIVES

B-cell MALT lymphoma is a well-recognized entity and its characterization as low-grade (LG) and high-grade (HG) lymphoma has been widely accepted. In the present study we reviewed a series of 95 surgical specimens of primary gastric MALT lymphoma selected between 1979 and 1998. Immunohistochemical expression of p53, bcl-2, and Ki67 and Helicobacter pylori (Hp) infection was evaluated, along with a correlation with clinical outcome.

METHODS

A morphologic and immunohistochemical analysis, including p53, bcl-2, and Ki67 expression, was carried out in all cases. A complete follow-up was obtained in 49 patients and in these cases a survival analysis was performed.

RESULTS

bcl-2 protein was highly expressed in 25 of 25 assessed LG tumors and in 20 of 24 assessed HG tumors. p53 protein was expressed in 13 of 25 assessed LG tumors and in 21 of 24 assessed HG tumors. High proliferation rate as expressed by Ki67 was detected in 15 of 25 assessed LG tumors and in 23 of 24 assessed HG tumors. Hp infection was detected in 11 of 16 assessed LG tumors and 2 of 10 assessed HG tumors. Median survival rates were 72 months for LG tumors and 24 months for HG tumors.

CONCLUSIONS

A significant inverse relationship between Hp infection and histological grade was found. High p53 expression and high-proliferation rate correlated with HG tumors. However, a correlation between p53, bcl-2, and Ki67 expression with clinical outcome was not found.

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

BACKGROUND

While the clinical and experimental knowledge concerning gastric lymphomas is increasing, there is a scarcity of epidemiological data.

PATIENTS AND METHODS

A population-based sample of patients in Franconia and Saarland in Germany was collected from a clinical trial, hospital archives and a cancer registry.

RESULTS

Over a period of 3 years, 94 patients with primary gastric lymphoma were recorded out of a total population of 3.5 million. The standardised incidence rates in Saarland and Franconia were 0.7 and 0.8 cases per 100 000, respectively. Patients were predominantly from higher age groups (mean age 62.1 years) and the incidence in men was slightly more than in women (P <0.03). The distribution of histological subtypes in Franconia was as follows: marginal zone B-cell lymphomas (MZBL), 58%; diffuse large-cell B-cell lymphoma (DLBL), 33%; and mixed forms, 9%. Helicobacter pylori could be detected histologically in 84% of all cases, 95% of MZBL cases and 68% of DLBL cases.

CONCLUSIONS

Incidence rates of gastric lymphoma in Germany were similar to that in other European countries, except England, where rates are lower. The subtype-specific differences of H. pylori infection rates could be due to differences in carcinogenesis or to secondary changes during malignant transformation.

A critical review of the effect of Helicobacter pylori eradication on gastric MALT lymphoma

Low-grade B-cell lymphomas of mucosa-associated lymphoid tissue (MALT) are thought to arise within organized lymphoid tissue in the gastric mucosa that is most frequently acquired in response to Helicobacter pylori infection. This close association between the organism and the lymphoma is further reflected by the demonstration that the proliferation of the lymphoma cells can be driven by the presence of H. pylori organisms through a complex path of cellular interactions involving specific T cells. From these observations it was suggested that removal of one of the proliferative drives to the neoplastic cells in the form of eradication of the organism might induce a remission in the tumor. Several large multicenter studies are now underway to consider this question, and interim reports suggest that long-term remissions can be induced in low-grade MALT lymphomas in 70% to 80% of cases. The lymphomas that are most likely to respond to H. pylori eradication are those that are located superficially within the gastric mucosa. It has been suggested that certain genetic abnormalities, such as t(11;18) and the Bcl-10 mutation, may be associated with lack of response to this therapy. Recurrences of low-grade lymphoma are encountered in patients treated by H. pylori eradication, but these appear to be infrequent and may be self-limiting and spontaneously regress without further therapy.

The role of Helicobacter pylori in primary gastric MALT lymphoma

AIMS

Helicobacter pylori has been claimed to be an important aetiological factor which raises the risk of mucosa-associated tissue lymphoid (MALT) lymphoma. However, some studies on gastric MALT lymphoma revealed a low rate of H. pylori infection suggesting that not all gastric lymphomas are related to H. pylori infection. The aim of this study was to verify the H. pylori infection frequency in a series of patients with primary gastric MALT lymphomas and to examine the relationship between H. pylori and the pathological features of those lymphomas.

METHODS AND RESULTS

Thirty-one cases of resected gastric lymphoma were analysed: 10 cases (32%) were low-grade MALT lymphomas and 21 cases (68%) were high-grade MALT lymphomas. Helicobacter pylori was found in only 18 of 31 (58%) cases. Helicobacter pylori infection was significantly correlated with the grade and depth of invasion of MALT lymphoma since 63% of superficial low-grade MALT lymphomas were positive for H. pylori compared with 38% of advanced high-grade MALT lymphomas (P = 0.02).

CONCLUSION

We confirmed the relationship between H. pylori infection and a subset of gastric MALT lymphoma. Our results also showed that not all low- and high-grade gastric MALT lymphomas are H. pylori-dependent. This suggests that H. pylori infection may play a promoter role in the development of MALT lymphoma, but its presence is not mandatory for the progression of the lymphoma in view of its low frequency in advanced high-grade MALT lymphoma.

Mucosa-associated lymphoid tissue lymphoma of the stomach: long term outcome after local treatment

BACKGROUND

Although antibiotic therapy is emerging as effective initial treatment for patients with gastric lymphoma of mucosa-associated lymphoid tissue (MALT), there is a subset of patients for whom antibiotics are ineffective or inappropriate. Surgical resection can be curative, but total gastrectomy may be required for the eradication of all disease. To identify the optimal nonantibiotic therapy for early stage gastric MALT lymphoma, the authors retrospectively evaluated the Massachusetts General Hospital experience with gastric MALT lymphoma.

METHODS

Disease patterns and treatment outcomes were retrospectively analyzed in data from 21 consecutive patients with gastric MALT lymphoma who were treated between 1978 and 1995 at the Massachusetts General Hospital.

RESULTS

Sixteen patients were Stage IE, and 5 were in higher stages. Treatment consisted of resection with or without radiation or chemotherapy (14 patients), radiation alone (4 patients), or radiation plus chemotherapy (2 patients). Thirteen Stage IE patients received local therapy only. The 10-year actuarial relapse free survival rate for Stage IE patients was 93%, with 1 relapse among 15 treated patients. Because the patient who relapsed was treated successfully with chemotherapy, the 10-year cancer free survival was 100%. Overall survival for Stage IE patients was 93% at 5 years and 58% at 10 years, with no deaths from lymphoma.

CONCLUSIONS

These data indicate that a high probability of long term remission can be achieved with only local treatment of patients with Stage I gastric MALT lymphoma. Preliminary results suggest that radiation therapy is well tolerated and effective and may well be the optimal nonantibiotic treatment for patients with localized gastric MALT lymphoma.