OUTCOMES OF ADULTS, ADOLESCENTS, AND CHILDREN WITH PRIMARY MEDIASTINAL B‐CELL LYMPHOMA TREATED WITH DOSE‐ADJUSTED EPOCH‐R THERAPY: a MULTICENTER RETROSPECTIVE ANALYSIS

Abstract

Introduction: Treatment with dose-adjusted EPOCH chemotherapy and rituximab (DA-EPOCH-R) has become the standard of care for primary mediastinal B-cell lymphoma (PMBCL) at many institutions despite limited data in the multi-center setting. We report a large, multi-center retrospective analysis of children and adults with PMBCL treated with DA-EPOCH-R to characterize outcomes, specifically assess both pediatric and adult patients, and to evaluate potential prognostic factors. Methods: 156 patients with PMBCL treated with DA-EPOCH-R across 24 academic medical centers were assessed, including 38 children and 118 adults. All patients received at least one cycle of DA-EPOCH-R. Radiation therapy was administered at the completion of DAEPOCH-R in 14.7% of patients. Results: With median follow-up of 22.6 months (range 2.7-101.0 months), the estimated 3-year EFS is 85.9% (95% CI 80.3-91.5) and OS is 95.4% (95% CI 91.8-99.0). Outcomes were similar in pediatric and adult patients. Pediatric patients were more likely to present with bulky mediastinal disease and were more likely to be escalated to at least dose level 4. Thrombotic complications were reported in 28.2% of patients and were more common in pediatric patients (45.9% vs. 22.9%, p = 0.011). The sites of thromboses included: upper extremity (n = 22), internal jugular vein or superior vena cava (n = 10), intracardiac (n = 5), pulmonary embolism (n = 5), and lower extremity (n = 2). Seventy-five percent of patients had a negative FDG-PET scan at the completion of DA-EPOCH-R, defined as Deauville score 1-3. Negative FDG-PET at end-of-therapy was associated with improved EFS (95.4% vs. 54.9%, p < 0.001). Conclusions: Our multicenter data support the use of DA-EPOCH-R for the treatment of PMBCL in children, adolescents, and adults with PMBCL. The high rate of thrombosis suggests that prophylactic anticoagulation should be considered in this setting. Patients with a positive end-of-therapy FDG-PET scan have an inferior outcome and may benefit from augmented or novel therapy.