Radiotherapy or not in patients with PMBCL after immunochemotherapy?

Omission of mediastinal radiotherapy in patients with primary mediastinal B-cell lymphoma (PMBCL) who had a complete metabolic response after first-line immunochemotherapy appeared safe, results from the IELSG37 trial demonstrated. The progression-free survival (PFS) and overall survival rates were comparable for patients who received radiotherapy and for those who did not.

There is conflicting evidence regarding the effectiveness of radiotherapy in patients with PMBCL [1,2]. The IELSG37 trial (NCT01599559) assessed whether mediastinal radiotherapy can be safely omitted in participants with PMBCL who had a complete metabolic response after standard immunochemotherapy [3]. All PET-negative participants after immunochemotherapy (n=268) were randomised 1:1 to mediastinal radiotherapy (30 Gy) or observation. The primary endpoint was PFS at 30 months. Dr Maurizio Martelli (University Sapienza Roma, Italy) presented the results.

The 30-month PFS rates were 98.5% in the radiotherapy arm and 96.2% in the observation arm (Log-rank P=0.27), demonstrating that there is no difference between the two study arms. The 30-month overall survival rates were 99.2% and 99.3%. Dr Martelli concluded that the omission of radiotherapy is safe in participants with PMBCL who had a complete metabolic response after first-line immunochemotherapy.

1. Jackson MW, et al. Am J Hematol. 2016;91(5):476–480
2. Dunleavy K, et al. N Engl J Med. 2013;368:1408–1416
3. Martelli M, et al. Omission of radiotherapy in primary mediastinal B-cell lymphoma patients following complete metabolic response to standard immunochemotherapy: results of the IELSG37 randomized trial. Plenary abstracts session, EHA 2023 Annual Congress, 8─11 June, Frankfurt, Germany.

Posted on 2 August 202323 April 2024