{"entity":{"id":"ielsg37","kind":"trial","name":"IELSG37","aka":[],"tldr":"IELSG37 showed that people with primary mediastinal B-cell lymphoma whose scan is clear after chemotherapy do not need radiotherapy to the chest, sparing young patients decades of heart and breast cancer risk.","summary":"IELSG37 registered 545 patients with primary mediastinal large B-cell lymphoma treated with rituximab-containing immunochemotherapy (mostly R-CHOP or dose-adjusted EPOCH-R, by centre) and randomised the 268 who reached a complete metabolic response on end-of-treatment PET (Deauville 1 to 3) to 30 Gy consolidation radiotherapy or to observation.\n\nProgression-free survival at 30 months was 96.7 percent without radiotherapy and 98.5 percent with it, within the non-inferiority margin, with no difference in overall survival. Patients with residual PET uptake were not randomised and received radiotherapy, in whom outcomes were also good.\n\nThe trial settled a forty-year argument: mediastinal radiotherapy can be omitted in the majority of patients who reach complete metabolic response, and PET now decides who is irradiated.","status":"positive","asOf":"2026-09-17","links":[{"label":"ClinicalTrials.gov NCT01599559","url":"https://clinicaltrials.gov/study/NCT01599559"},{"label":"Journal of Clinical Oncology 2024","url":"https://doi.org/10.1200/JCO.24.01373"}],"tags":[],"related":[],"cancers":["primary-mediastinal-b-cell-lymphoma"],"sections":[],"technologies":["fdg-pet","pet-adapted-therapy","imrt-igrt"],"targets":[],"drugs":["rituximab"],"companies":[],"institutions":[],"pathways":[],"terms":["deauville-score","r-chop","lugano-classification"],"trials":[],"people":[],"bottlenecks":[],"keyPapers":[],"journals":[],"dependsOn":[],"notes":[],"nct":"NCT01599559","phase":"3","setting":"Primary mediastinal large B-cell lymphoma in complete metabolic response on PET after rituximab-based immunochemotherapy: consolidation mediastinal radiotherapy versus observation","sponsor":"International Extranodal Lymphoma Study Group","result":"30-month progression-free survival 96.7% (observation) vs 98.5% (radiotherapy) in patients with complete metabolic response; radiotherapy can be omitted.","yearReported":2024,"enrolled":545,"outcomes":[{"endpoint":"Progression-free survival at 30 months","primary":true,"unit":"%","arms":[{"name":"Observation","n":132,"value":96.7},{"name":"Consolidation radiotherapy 30 Gy","n":136,"value":98.5}],"source":"https://doi.org/10.1200/JCO.24.01373"}],"replication":"Consistent with the single-arm National Cancer Institute DA-EPOCH-R series, in which no patient received radiotherapy and event-free survival was 93 percent."},"route":"/trials/ielsg37/","neighbours":{"cancer":[{"id":"primary-mediastinal-b-cell-lymphoma","kind":"cancer","name":"Primary mediastinal (thymic) large B-cell lymphoma","route":"/cancers/primary-mediastinal-b-cell-lymphoma/"}],"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":"pet-adapted-therapy","kind":"technology","name":"PET-adapted (response-adapted) therapy","route":"/technologies/pet-adapted-therapy/"}],"drug":[{"id":"rituximab","kind":"drug","name":"Rituximab","route":"/drugs/rituximab/"}],"term":[{"id":"deauville-score","kind":"term","name":"Deauville five-point scale","route":"/terms/deauville-score/"},{"id":"lugano-classification","kind":"term","name":"Lugano classification / Ann Arbor staging","route":"/terms/lugano-classification/"},{"id":"r-chop","kind":"term","name":"R-CHOP (lymphoma chemoimmunotherapy)","route":"/terms/r-chop/"}]}}