Stem Cell Transplantation for Pediatric Patients with Non-Anaplastic Peripheral T-Cell Lymphoma on Behalf of the EBMT-Pediatric Diseases Working Party

Peripheral T-cell lymphomas (PTCL) other than anaplastic large cell lymphoma are rare in children, and data about outcome and treatment results especially regarding the role of stem cell transplantation (SCT) are scarce. Here we present the results of a retrospective study of SCT for pediatric patients with PTCL within the European Group of Bone marrow transplantation (EBMT). Out of 125 patients aged <18 years with PTCL diagnosed between 1995 and 2015 who were registered to the EBMT database, reports about the primary therapy and data about the course of SCT were sufficient for analysis in 55 patients. 37 (69%) had PTCL not otherwise specified (NOS), 7 (13%) hepato-splenic T-cell lymphoma, 4 (7%) angioimmunoblastic T-cell lymphoma, 3 (6%) NK/T-cell lymphoma, 2 (4%) subcutaneous panniculitis-like T-cell lymphoma, and 1 systemic EBV-lymphoproliferative syndrome. Median age at PTCL-diagnosis was 13.0 years (range: 0.7-17.6), and was 13.9 years (range: 2.5-17.9) at SCT, respectively. 35 (65%) of the patients were male. 43 (81%) of the patients had received T-NHL/ lymphoblastic lymphoma-type therapy; radiotherapy (RT) was given to 7 patients (16%) prior to SCT. 45 (83%) patients underwent allogeneic SCT (16 from related and 29 from unrelated donor), and 9 (17%) patients received autologous SCT (ASCT). Myeloablative conditioning (MAC) was used in 44 (88%) patients, 6 (12%) patients received reduced-intensity conditioning (RIC). Total body irradiation (TBI) was part of the conditioning regimen in 26 patients (48%).

After SCT the 5-year overall survival (OS) and lymphoma-free survival (LFS) probability was 57% (95% CI 44.5-72.5) and 56% (95% CI 43.4-71.2), respectively. Relapse incidence was 25% (95% CI 14.1-37.9), whereas the non-relapse mortality (NRM) rate was 18% (95% CI 9.4-29.7).

Patients with younger age (0-9 years, vs. 10-18 years) at diagnosis of PTCL had a tendency for better outcome (OS 80% vs. 50%, respectively p=0.069), whereas age at SCT and gender had no influence on outcome (p=0.2 and p=0.6, respectively). Year of SCT (1995-2007 vs. 2008-2015) was of no significance for the outcome (p=0.31).

A tendency for better outcome (OS/LFS) was observed in patients who received RT in the pre-transplant treatment, and for patients who achieved first/second complete remission (CR1/CR2) before SCT, as compared to those with later/ without CR prior to SCT (OS 72% vs 46%, p=0.1). Patients receiving MAC conditioning had a better OS compared to patients receiving RIC (66% vs. 33%, p=0.07). LFS was inferior after ASCT compared to allogeneic SCT, resulting in non-significant difference in OS .

Acute Graft-versus host disease (aGvHD) grade III/IV was seen in 6 (14.6%) patients. 6 patients suffered from chronic GvHD, 2 of them from the extensive form.

In conclusion, SCT for pediatric patients with PTCL in CR1/CR2 is a valid option of treatment. MAC may currently be chosen for conditioning in order to possibly prevent relapses.