Outcome Of Hematopoietic Cell Transplantation (HCT) In Pediatric Patients With Non-Hodgkin Lymphoma (NHL): Single Institution Results From Saudi Arabia

Although HCT is an accepted component of the treatment strategy for relapsed/refractory pediatric NHL, only few studies have reported on the outcome for these patients. Most have reported on small numbers of patients, with survivals ranging from 27% to 75%.

Clinical data were retrospectively retrieved for patients with NHL who had undergone HCT. Pre-HCT information, including pathologic diagnosis, response to first- and second-line therapy and pre-HCT disease status were collected, in addition to details of the transplant process and patient and disease outcome.

Between 1996 and 2012, 28 pediatric patients with NHL underwent HCT. Primary diagnosis for these patients included Burkitt lymphoma (n=13), Large B-cell lymphoma (n=4), T-Lymphoblastic lymphoma (n=4), NK/T cell lymphoma/leukemia (n=3), Peripheral T-cell lymphoma (n=2), B-lymphoblastic lymphoma ((n=1) and anaplastic large cell lymphoma (n=1). The median age at HCT was 7.65 years (mean 8.2; range 1-14.3). Twenty had suffered a relapse of their disease, while five had primary progression; three patients with NK/T lymphomas underwent HCT as part of their first-line therapy. Fourteen patients had autologous (autoHCT) and 14 had allogeneic HCT (alloHCT). Among alloHCT, 11 had matched-related grafts while 3 had unrelated umbilical cord blood (UCB) grafts. At the time of HCT, 23 patients were in CR (CR1=7, CR2=15, CR3=1), and 5 had partial responses. HCT conditioning was myeloablative for all patients; in 18 patients, it was TBI-based. Fourteen patients suffered recurrence of their lymphoma post HCT at a median of 1.17 months from HCT (mean 6.2; range 0.63-42); 4 died in CR due to transplant-related toxicity, of these 3 were post alloHCT and one post autoHCT. Three patients have developed secondary malignancies (SMN; 2 post alloHCT and 1 post autoHCT). 10 patients were alive at last follow-up, all of whom were in CR. The 5-year estimated OS from SCT is 38.7%, with and EFS of 26%. There was no difference in 5-year OS or EFS among patients who received alloHCT v. autoHCT (OS 28.6% v. 49%; p=0.53, EFS 14.3% v. 37.5%; p=0.25) and among patients who did or did not receive TBI (OS 33.3% v. 48%; p=0.37, EFS 27.8% v. 18.8%; p=0.66). OS/EFS for patients with Burkitt lymphoma was 23.1%. Of the three patients with NK/T cell lymphoma two remain alive in CR 13.7 and 5.1 years after HCT.

The outcome of relapsed/refractory non-Hodgkin lymphoma of childhood remains suboptimal. In addition to a high post-HCT relapse rate of 50%, HCT-related toxic mortality and SMN contribute to the poor outcome for this cohort of patients.