A retrospective study of 5-year outcomes of radiotherapy for gastric mucosa-associated lymphoid tissue lymphoma refractory to Helicobacter pylori eradication therapy.

BACKGROUND The favorable response rate of radiotherapy for localized gastric mucosa-associated lymphoid tissue lymphoma refractory to Helicobacter pylori eradication has been demonstrated. However, there are limited data available on the long-term outcomes. The aim of this retrospective study was to evaluate the long-term outcomes of radiotherapy for localized gastric mucosa-associated lymphoid tissue lymphoma refractory to Helicobacter pylori eradication. METHODS Thirty-four consecutive patients with localized gastric mucosa-associated lymphoid tissue lymphoma that were refractory to eradication were treated with radiotherapy (a total dose of 30 Gy). The response and adverse events of radiotherapy were retrospectively analyzed as short-term outcomes, and recurrence-free, overall and disease-specific survival rates were calculated as long-term outcomes. RESULTS Thirty-three (97.1%) patients achieved complete remission and radiotherapy was well tolerated. One patient underwent emergency gastrectomy due to severe hematemesis. Of the 34 patients during the median follow-up period of 7.5 (1.2-13.0) years, one patient had local recurrence after 8.8 years, one patient underwent surgery for bowel obstruction secondary to small bowel metastasis after 5.1 years and one patient had pulmonary metastasis after 10.9 years. Pathologically, all three recurrences revealed mucosa-associated lymphoid tissue lymphoma without any transformation to high-grade lymphoma. None died of gastric mucosa-associated lymphoid tissue lymphoma. The 5-year recurrence-free survival rate was 97.0%. The 5-year overall survival rates and disease-specific survival rates were 97.0 and 100%, respectively. CONCLUSIONS Radiotherapy in patients with localized gastric mucosa-associated lymphoid tissue lymphoma refractory to Helicobacter pylori eradication can achieve excellent overall survival. However, long-term surveillance is necessary to identify late recurrences.