Endoscopic ultrasonography for assessment of medical treatment in patients with gastric mucosa‐associated lymphoid tissue lymphoma

Abstract

Background: Although gastric mucosa‐associated lymphoid tissue (MALT) lymphoma often regresses after medical treatment, it is not known whether submucosal lymphomatous involvement persists. Because sampling error is a problem associated with histological evaluation and endoscopic ultrasonography (EUS) is appropriate for assessing the depth of infiltration in cases of gastric lymphoma, we investigated the value of EUS for assessing the effectiveness of medical treatment. Methods: Twelve patients with gastric MALT lymphoma were treated with Helicobacter pylori eradication therapy and/or chemotherapy. Endoscopic ultrasonography was done at initial staging and after treatment. We used EUS to measure the distance from the surface layer to the deepest part of the hypoechoic area; a distance of less than 1.3 mm was considered normal. Results: The mean depth of the hypoechoic area in MALT lymphoma‐positive biopsy specimens was significantly greater than that in MALT lymphoma‐negative biopsy specimens. In many cases in which MALT lymphoma disappeared after treatment, the depth of the endoscopic ultrasonographic hypoechoic area also decreased to normal. In two cases, however, in which the MALT lymphoma biopsy results were negative but there was no decrease to normal depth, recurrence occurred during follow up. Conclusion: Our results show that measurement of the depth of the hypoechoic area via EUS is useful in assessing the response of gastric MALT lymphoma to treatment. When the depth of the hypoechoic area does not decrease to normal, careful follow up and frequent biopsies are required.