{"entity":{"id":"ielsg","kind":"company","name":"International Extranodal Lymphoma Study Group","aka":["IELSG"],"tldr":"A Swiss-based international group that runs the trials defining treatment of rare extranodal lymphomas, including primary CNS lymphoma and gastric MALT lymphoma.","summary":"Founded in 1997 and coordinated from the Oncology Institute of Southern Switzerland in Bellinzona, IELSG focuses on lymphomas arising outside lymph nodes, which no single country can study alone. IELSG32 established the MATRix regimen and consolidation strategies in primary CNS lymphoma, IELSG37 tested omission of mediastinal radiotherapy after PET-negative response in primary mediastinal B-cell lymphoma, and its gastric MALT lymphoma studies defined antibiotic and chlorambucil-rituximab therapy. It collaborates with LYSA, HOVON, the Nordic Lymphoma Group and Australian groups.","asOf":"2026-09-09","links":[{"label":"IELSG","url":"https://www.ielsg.org"}],"tags":["cooperative-group"],"related":[],"cancers":["dlbcl"],"sections":["radiation","chemotherapy"],"technologies":["fdg-pet","monoclonal-antibody","imrt-igrt"],"targets":[],"drugs":[],"companies":["lysa","hovon","nordic-lymphoma-group"],"institutions":[],"pathways":[],"terms":[],"trials":[],"people":["franco-cavalli"],"bottlenecks":[],"keyPapers":[],"journals":[],"dependsOn":[],"notes":["Primary CNS lymphoma (IELSG32, IELSG43)","Primary mediastinal B-cell lymphoma (IELSG37)","MALT lymphoma","Rare extranodal lymphoma registries"],"provenance":{"editedBy":"OnCo cooperative groups migration (row 251: institution consortium records moved to cooperative-group companies)","editedOn":"2026-09-25"},"hq":"Bellinzona","country":"CH","companyType":"cooperative-group","website":"https://www.ielsg.org","founded":1997,"investors":[],"funding":[]},"route":"/companies/ielsg/","neighbours":{"cancer":[{"id":"dlbcl","kind":"cancer","name":"Diffuse large B-cell lymphoma","route":"/cancers/dlbcl/"}],"section":[{"id":"chemotherapy","kind":"section","name":"Chemotherapy","route":"/fronts/chemotherapy/"},{"id":"radiation","kind":"section","name":"Radiation Therapy","route":"/fronts/radiation/"}],"technology":[{"id":"fdg-pet","kind":"technology","name":"FDG PET","route":"/technologies/fdg-pet/"},{"id":"imrt-igrt","kind":"technology","name":"IMRT / IGRT (modern external beam)","route":"/technologies/imrt-igrt/"},{"id":"monoclonal-antibody","kind":"technology","name":"Monoclonal antibodies","route":"/technologies/monoclonal-antibody/"}],"company":[{"id":"hovon","kind":"company","name":"HOVON","route":"/companies/hovon/"},{"id":"lysa","kind":"company","name":"LYSA (The Lymphoma Study Association)","route":"/companies/lysa/"},{"id":"nordic-lymphoma-group","kind":"company","name":"Nordic Lymphoma Group","route":"/companies/nordic-lymphoma-group/"}],"person":[{"id":"andres-ferreri","kind":"person","name":"Andrés J. M. Ferreri","route":"/people/andres-ferreri/"},{"id":"franco-cavalli","kind":"person","name":"Franco Cavalli","route":"/people/franco-cavalli/"}],"trial":[{"id":"ielsg-19","kind":"trial","name":"IELSG-19","route":"/trials/ielsg-19/"},{"id":"ielsg32","kind":"trial","name":"IELSG32","route":"/trials/ielsg32/"},{"id":"ielsg37","kind":"trial","name":"IELSG37","route":"/trials/ielsg37/"},{"id":"ielsg43","kind":"trial","name":"MATRix/IELSG43","route":"/trials/ielsg43/"},{"id":"prima-cns","kind":"trial","name":"PRIMA-CNS","route":"/trials/prima-cns/"}],"paper":[{"id":"paper-ielsg-19-chlorambucil-rituximab-malt-jco-2017","kind":"paper","name":"Final results of the IELSG-19 randomized trial of mucosa-associated lymphoid tissue lymphoma: improved event-free and progression-free survival with rituximab plus chlorambucil versus either chlorambucil or rituximab monotherapy","route":"/key-papers/paper-ielsg-19-chlorambucil-rituximab-malt-jco-2017/"}],"institution":[{"id":"iosi-bellinzona","kind":"institution","name":"Oncology Institute of Southern Switzerland (IOSI)","route":"/institutions/iosi-bellinzona/"}]}}