Effect of radiotherapy on MALT lymphomas not responding to H. pylori eradication

Gastric and duodenal mucosa-associated lymphoid tissue (MALT) lymphomas were classified into 4 groups (Group A, B, C, and D) by the existence of API2-MALT1 chimeric transcript, H. pylori infection and its response to H. pylori eradication. Cases in group A were API2-MALT1 negative, H. pylori positive which responded to H. pylori eradication. Non responders were classified into group B. Cases in group C were API2-MALT1 negative and H. pylori negative. Group D was API2-MALT1 positive. Twenty two cases of clinical stage I in group B, C and D which did not respond to eradication (2 cases also had chemotherapy) received radiotherapy and all of them achieved complete response. Acute toxicities were only grade 1 digestive symptoms and grade 1-2 hematologic toxicities and late toxicity was seen in only one case as grade 2 nephropathy. Nephropathy was avoided by the multi-field technique instead of the 2-field technique. Radiotherapy can be an effective and safe treatment for gastric and duodenal MALT lymphomas in clinical stage I. (author)