A case of gastric lymphoma with marked interfractional gastric movement during radiation therapy.

Radiation therapy (RT) with or without chemotherapy has been a widely accepted treatment for patients with localized gastric lymphoma. We encountered a patient with gastric diffuse large B-cell lymphoma, whose stomach volume, and the position and location of the clips that had been endoscopically placed to define the gastric lesions clearly differed considerably at three simulation times. The positions of the clips moved between 5 and 35 mm (mean 24 mm) laterally on simulation films. The mean movement of these clips along the cephalocaudal directions was 8 mm (range 0-15 mm). There have been no published articles which systemically evaluated interfractional gastric motion between each treatment session. Therefore this is an important observation in the management of patients with gastric lymphoma with RT.