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Omission of Radiotherapy in Primary Mediastinal B-Cell Lymphoma: IELSG37 Trial Results

Martelli, M. ; Jerkeman, M. LU and Zucca, Emanuele (2024) In Journal of Clinical Oncology 42(34). p.4071-4083
Abstract
PURPOSE The role of consolidation radiotherapy in patients with primary mediastinal B-cell lymphoma (PMBCL) is controversial. METHODS The IELSG37 trial, a randomized noninferiority study, aimed to assess whether irradiation can be omitted in patients with PMBCL with complete metabolic response (CMR) after induction immunochemotherapy. The primary end point was progression-free survival (PFS) at 30 months after random assignment. Patients with CMR were randomly assigned to observation or consolidation radiotherapy (30 Gy). With a noninferiority margin of 10% (assuming a 30-month PFS of 85% in both arms), a sample size of 540 patients was planned with 376 expected to be randomly assigned. RESULTS The observed events were considerably lower... (More)
PURPOSE The role of consolidation radiotherapy in patients with primary mediastinal B-cell lymphoma (PMBCL) is controversial. METHODS The IELSG37 trial, a randomized noninferiority study, aimed to assess whether irradiation can be omitted in patients with PMBCL with complete metabolic response (CMR) after induction immunochemotherapy. The primary end point was progression-free survival (PFS) at 30 months after random assignment. Patients with CMR were randomly assigned to observation or consolidation radiotherapy (30 Gy). With a noninferiority margin of 10% (assuming a 30-month PFS of 85% in both arms), a sample size of 540 patients was planned with 376 expected to be randomly assigned. RESULTS The observed events were considerably lower than expected; therefore, primary end point analysis was conducted when ≥95% of patients were followed for ≥30 months. Of the 545 patients enrolled, 268 were in CMR after induction and were randomly assigned to observation (n = 132) or radiotherapy (n = 136). The 30-month PFS was 96.2% in the observation arm and 98.5% in the radiotherapy arm, with a stratified hazard ratio of 1.47 (95% CI, 0.34 to 6.28) and absolute risk difference of 0.68% (95% CI, -0.97 to 7.46). The 5-year overall survival (OS) was 99% in both arms. Nonrandomized patients were managed according to local policies. Radiotherapy was the only treatment in 86% of those with Deauville score (DS) 4 and in 57% of those with DS 5. The 5-year PFS and OS of patients with DS 4 (95.8% and 97.5%, respectively) were not significantly different from those of randomly assigned patients. Patients with DS5 had significantly poorer 5-year PFS and OS (60.3% and 74.6%, respectively). CONCLUSION This study, the largest randomized trial of radiotherapy in PMBCL, demonstrated favorable outcomes in patients achieving CMR with no survival impairment for those omitting irradiation. © 2024 by American Society of Clinical Oncology. (Less)
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Contribution to journal
publication status
published
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in
Journal of Clinical Oncology
volume
42
issue
34
pages
13 pages
publisher
Lippincott Williams & Wilkins
external identifiers
  • scopus:85203192890
  • pmid:39159403
ISSN
0732-183X
DOI
10.1200/JCO-24-01373
language
English
LU publication?
yes
id
c425e8eb-b33d-473f-99e7-f6ea1889aee0
date added to LUP
2025-01-10 13:24:55
date last changed
2025-04-04 15:19:38
@article{c425e8eb-b33d-473f-99e7-f6ea1889aee0,
  abstract     = {{PURPOSE The role of consolidation radiotherapy in patients with primary mediastinal B-cell lymphoma (PMBCL) is controversial. METHODS The IELSG37 trial, a randomized noninferiority study, aimed to assess whether irradiation can be omitted in patients with PMBCL with complete metabolic response (CMR) after induction immunochemotherapy. The primary end point was progression-free survival (PFS) at 30 months after random assignment. Patients with CMR were randomly assigned to observation or consolidation radiotherapy (30 Gy). With a noninferiority margin of 10% (assuming a 30-month PFS of 85% in both arms), a sample size of 540 patients was planned with 376 expected to be randomly assigned. RESULTS The observed events were considerably lower than expected; therefore, primary end point analysis was conducted when ≥95% of patients were followed for ≥30 months. Of the 545 patients enrolled, 268 were in CMR after induction and were randomly assigned to observation (n = 132) or radiotherapy (n = 136). The 30-month PFS was 96.2% in the observation arm and 98.5% in the radiotherapy arm, with a stratified hazard ratio of 1.47 (95% CI, 0.34 to 6.28) and absolute risk difference of 0.68% (95% CI, -0.97 to 7.46). The 5-year overall survival (OS) was 99% in both arms. Nonrandomized patients were managed according to local policies. Radiotherapy was the only treatment in 86% of those with Deauville score (DS) 4 and in 57% of those with DS 5. The 5-year PFS and OS of patients with DS 4 (95.8% and 97.5%, respectively) were not significantly different from those of randomly assigned patients. Patients with DS5 had significantly poorer 5-year PFS and OS (60.3% and 74.6%, respectively). CONCLUSION This study, the largest randomized trial of radiotherapy in PMBCL, demonstrated favorable outcomes in patients achieving CMR with no survival impairment for those omitting irradiation. © 2024 by American Society of Clinical Oncology.}},
  author       = {{Martelli, M. and Jerkeman, M. and Zucca, Emanuele}},
  issn         = {{0732-183X}},
  language     = {{eng}},
  number       = {{34}},
  pages        = {{4071--4083}},
  publisher    = {{Lippincott Williams & Wilkins}},
  series       = {{Journal of Clinical Oncology}},
  title        = {{Omission of Radiotherapy in Primary Mediastinal B-Cell Lymphoma: IELSG37 Trial Results}},
  url          = {{http://dx.doi.org/10.1200/JCO-24-01373}},
  doi          = {{10.1200/JCO-24-01373}},
  volume       = {{42}},
  year         = {{2024}},
}