Is endoscopic ultrasound clinically useful for follow-up of gastric lymphoma?

Background: Endoscopic ultrasound (EUS) is considered the best technique for locoregional staging at diagnosis but its role in the follow-up of patients with gastric lymphoma after organ-conserving strategies has not been established. Design and methods: We retrospectively evaluated 23 patients with primary gastric lymphoma treated with a stomach-conservative approach. Sixteen of them were affected by MALT lymphoma and seven by diffuse large-B-cell lymphoma (DLBCL). Five patients were treated with Helicobacter pylori (HP) eradication therapy alone (omeprazole + amoxicillin + clarithromycin); eight patients received a treatment including HP eradication and chemotherapy and the remaining 10 patients were treated with chemotherapy alone. Results: At the end of treatment, a complete remission was documented in 21 (91%) patients by endoscopy with biopsy (E-Bx) but in only seven (30%) patients by EUS. A total of 99 evaluations with both EUS and E-Bx were evaluated and we found concordance between the two methods in 33 occasions (33%) only. No significant difference on the percentage of concordance was recorded between MALT and DLBCL. After a median follow-up of 36.5 months we have not observed any relapse in 12 patients (six DLBCL and six MALT) with a persistent positive EUS but negative E-Bx. Conclusions: Although the length of follow-up cannot exclude late relapse, we think that in restaging and follow-up of gastric lymphoma, EUS seems not to be a reliable tool if it is abnormal and E-Bx still remains the gold standard. Therefore, after conventional conservative treatment, persistence of EUS abnormality with a negative histology should not be considered as a clinically relevant persistence of disease and should not be a reason for further treatment.