Allogeneic Hematopoietic Stem Cell Transplantions in Blastic Plasmacytoid Dendritic Cell Neoplasm in first complete remission: an effective therapy for a rare disease
Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a clinically aggressive tumor derived from the precursors of plasmacytoid dendritic cells (pDC) with a high frequency of primary cutaneous involvement, and dissemination to bone marrow with disease progression.[1] Median age at presentation is 60 to 70 years with a male predominance (3:1) Most BPDCN patients present with skin lesions that include nodules, plaques, or bruise like areas with lymphadenopathy or bone marrow Involvement.[2] BPDCN represents only 0.76% of cases presenting in the leukemic phase as acute leukemia.[3] Given the rarity of this hematologic malignancy, the optimal frontline therapy is unclear. Recent data suggest that BPDCN patients treated with acute lymphoblastic leukemia (ALL) type regimens, with or without allogeneic hematopoietic cell transplant (alloHCT) may have a better outcome.[4] There are no published randomized controlled trials evaluating the role of autologous hematopoietic cell transplant (autoHCT) or allo HCT in these patients. Our center had presented recently, excellent remission rates with HyperCVAD therapy.[5] Here we present the Allo HCT data in this group of patients. Our retrospective analysis evaluates the outcome of 6 patients who were diagnosed with BPDCN and underwent allo HCT at the Princess Margaret Cancer Centre. The study was approved by the Institutional Review Board of the hospital. All six patients were in leukemic phase at presentation, with five patients having skin involvement. All these patients were diagnosed by 10 color flow cytometry by using the panel published recently.[6] The basis for diagnosis was similar to that formulated by Garnache Ottou et al.[7] with CD4, CD56 and CD123 positivity in all patients. Prior to transplant 5 out of 6 patients underwent HyperCVAD as the ALL type chemotherapy for remission induction, one patient was treated with a combination of Fludarabine and L Asparginase. All patients were transplanted in first Complete Remission (CR1) with median time of 4.5 months to undergo allo HCT from achievement of CR1. The median age at transplant was 44 years (range, 25 to 70 years) with female preponderance (2M:4F) The myeloablative regimen (MAC) used was, Cyclophosphamide 60 mg/kg/day 2 days/Total Body Irradiation 200 cGy 6 doses (Cy/TBI) in patients with age 60 years (n1/4 3) and Fludarabine 30 mg/m/day 4 days/Busulphan 3.2 mg/kg/day 2 days/Total Body Irradiation 200 cGy 1 dose(FBT 200) was used as reduced intensity conditioning (RIC) in patients with age460 years (n1/4 3) Graft versus host disease (GVHD) prophylaxis was cyclosporine and mycophenolate in related donors with the addition of one dose of alemtuzumab to cyclosporine in unrelated donor transplantation. Two patients received stem cell transplants from sibling donors (6/6 HLA matched) and the remaining patients from matched unrelated donors (10/10 allelic HLA matched) The graft source was peripheral blood stem cells (PBSC) in all patients. The CD34 cell dose varied from 3.7 to 37.86 with mean cell dose was 14.75 10/kg of recipient body weight. The median time for neutrophil and platelet engraftment was 13.5 (range, 11 17 days) and 13 days (range,
Leukemia lymphoma