Study algorithm. 1Diagnostic biopsies underwent centrally pathology review.6 2Baseline and staging procedures: hemogram, biochemical profile, HIV, hepatitis B and C viruses' infection markers, contrasted thorax-abdomen CT scan, bone marrow biopsy, breath test, gastroscopy with at least 5 biopsies for each lesion and random sampling of residual normal mucosa, and echoendoscopy to evaluate gastric wall thickness and perigastric lymph nodes. The choice of areas suitable for biopsies was driven by echoendoscopy. Hp infection was confirmed by gastric biopsies ± breath test. 3Perigastric lymphadenopathies of a diameter < 1.5 cm were admitted to avoid a potential selection bias related to specificity limits of echoendoscopy. This cut-off was in line with the cut-off value used by standardized lymphoma criteria to define lymph-node infiltration when assessed by non-functional exams.7 4Sample size was not prospectively estimated in comparison with ORR reported with conventional chemo-radiotherapy (90%-100%) since it would request a non-inferiority design and hundreds of patients. Written informed consent was obtained from each registered patient; the trial conformed to the tenets of the Declaration of Helsinki and was approved by the IRB of participating centers. 5Patients who failed eradication received a second-line antibiotic therapy following local guidelines. 6The primary end point was overall response rate (ORR) after Hp eradication. Response was defined according to standardized criteria.7 Residual macroscopic abnormalities at endoscopic examination or residual perigastric lymph nodes measuring < 1 cm in diameter or gastric wall alterations at ultrasonography were considered as CR if histopathologic examination did not show lymphomatous infiltration. Persistence of areas of MALT and/or DLBCL in histopathologic specimens in patients with normal/improved gastric aspect at endoscopy and ultrasonography were considered as PR. 7Enhanced total-body CT scan was performed to exclude systemic dissemination. 8Physical examination, hemogram and biochemical profile, gastroscopy, gastric echoendoscopy, and enhanced CT scan every 3 months for the first 2 years, every 6 months from the 3rd to the 5th year, and once a year from the 6th to the 10th year. 9CHOP or CHOP-like regimens ± rituximab ± radiotherapy (physician's preference).
