Non-Gastric Advanced MALT Lymphoma Demonstrated Worse Prognosis Than Gastric MALT Lymphoma Even Treated by Rituximab-Combined chemotherapy.

Next to diffuse large B-cell lymphoma and follicular lymphoma, extranodal marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue (MALT lymphoma) is the third most common subtype of non-Hodgkin's lymphomas. Their clinical course usually is indolent with long-progression free survival (PFS) and overall survival (OS). Because it can involve many sites throughout the body, a patient of MALT lymphoma is often treated by different strategies, radiation therapy, surgery, or chemotherapy. The aims of study are to assess the clinical characteristics and treatment results of this one of the most common lymphoma and to analyze the prognostic factors.

Ninety-eight patients with MALT lymphoma consecutively diagnosed by an expert hematopathologist from March 2001 to October 2008 were reviewed retrospectively. They all underwent standarlized staging program in our hospital. Majority of the patients had localized disease. Comparisons were performed between patients with gastric and non-gastric MALT lymphoma. Prognostic significance of various factors for PFS was examined. Statistical analyses of PFS and OS were calculated using Kaplan-Meier estimators. Comparison among categories was performed by means of log-rank test. Using Cox proportional hazards regression analysis, multivariate analysis was performed about estimated risk factors.

Patients were 48 males and 50 females. Median age was 62 years old (range 26 to 85 years old). Only 17 patients had advanced diseases. 52 had the primary site located in the stomach, and 22 had in the orbit, and 8 had in the salivary grand. Ninety-three patients received some treatment, including radiation, chemotherapy and surgery. Mainly, localized gastric lymphoma and non-gastric lymphoma were performed eradication of Helicobacter Pylori and the radiation therapy respectively. All but two patients with disseminated diseases treated with rituximab-combined chemotherapy. The response rate of the initial treatment was 94%, and the CR rate was 76%. After a median follow-up time of 40 months (range 1 to 109 months), 3-years OS and PFS were 100% and 89%, respectively. 3-year PFS for localized disease and advanced disease were 94% and 73%, respectively. 3-years PFS was 95% for gastric MALT lymphoma and 82% for non-gastric lymphoma. All of the patients with localized gastric MALT lymphoma were progression-free at three years after the treatment. Adverse prognostic factors for PFS were non-gastric lymphoma and disseminated disease. In a multivariate analysis, shorter PFS was associated with non-gastric lymphoma.

Our analysis indicates that MALT lymphoma is an indolent disease with long survival, but patients with non-gastric lymphoma and advanced diseases were prone to have worse prognosis. H.pilori eradication was an effective first-line treatment for the localized gastric MALT lymphoma and leads to a favorable long term out-come. Rituximab-combined chemotherapy was effective even though for advanced disease. In this rituximab era, clinical course of this indolent lymphoma may become much better. However, the therapeutic strategy of MALT lymphoma is still controversial. We need to assess and clear up which is the best.

No relevant conflicts of interest to declare.