TREATMENT RESULTS ACCORDING TO CELLULAR SUBTYPES OF GASTRIC MALT LYMPHOMA

Abstract

Introduction: Although gastric MALT lymphoma is rare disorder, much work have been done. However, relationship between its treatment methods by histological subtypes has not well studied. In particular, role of etiologic factors may be different in various cellular subtypes of gastric MALT lymphoma, and this may change the treatment strategy of disease. Methods: We analyzed the treatment results of 106 patients with MALTS, average age of 54.7 ± 0.4 years. Men was 37 (34.9%), 69 women (65.1%). Histological verification of small-cell type of tumor found in 49 (46.2%) patients, intermediate type in 35 (33.0%) and in 22 (20.8%) mixed type lymphoma of the stomach. By classification of Lugano (1993) 1st stage in 69 (65.1%) patients, IIE in 14 (13,2%), II1 in 16 (15,1%), II2 in 7 (6,6%). Contamination degree by H.Pylori was defined as mild, moderate and high. Each histological subtype analyzed according to contamination degree by H.Pylori. Patients with high contamination degree underwent eradication therapy, moderate degree – eradication + chemotherapy (CHOP) and mild degree – chemotherapy. Rituximab was used in CD20 positive samples. Results: A total of 36 patients of small cellular subtype patients were high degree contamination, and we recommended eradication therapy. Complete response rate was 69.4% during one-year observation period. In recurrent cases, we used chemotherapy and achieved complete response, but 3 of them had complication of bleeding and carried out gastric resection. Other patients were moderate and mild degree contamination and checked for CD20 and 12 out of them were positive. We recommended rituximab with chemotherapy. Complete response was 100% in 36 months observation. Patients with intermediate cellular type were (20 patients) 57.1% H.Pylori high contamination degree and underwent eradication therapy. However, complete response was 45%. CD20 was positive in all recurrent cases and in patients with other degrees of contamination. Using rituximab gave 90% complete response and 2 patients developed complications with bleeding. A total of 18 patients of mixed cellular subtype were mild and moderate degree contamination, and CD20 was positive in all patients. We recommended chemotherapy with rituximab, and complete response was 81.8% (15 out of 18); 4 patients were high degree contamination, but we could not achieve complete response and recommended chemotherapy with rituximab. Complete response was 100% in 38-month observation period. Conclusion: Eradication therapy has beneficial effects in small cellular subtype with high contamination degree. However, its effectiveness is low in other cellular subtypes. Treatment with rituximab and chemotherapy was effective in CD20 cases with mild and moderate degree of contamination and in recurrent cases. Keywords: CD20; Mucosa-Associated Lymphoid Tissue (MALT); rituximab.