Allogeneic Hematopoietic Cell Transplantation Is an Effective Treatment for Blastic Plasmacytoid Dendritic Cell Neoplasm in First Complete Remission: Systematic Review and Meta-analysis

Introduction: It is common practice to refer patients to transplantation centers for allogeneic hematopoietic cell transplantation (allo-HCT) for blastic plasmacytoid dendritic-cell neoplasm (BPDCN) despite lack of randomized controlled trials. We performed a systematic review to assess the totality of evidence pertaining to the efficacy of allo-HCT in BPDCN.

Methods: We searched the Cochrane, PubMed, and Embase databases through January 5, 2018, for studies on allo-HCT for BPDCN. Two authors independently reviewed all references for inclusion and extracted data related to benefits (overall [OS] and progression-free/disease-free [PFS/DFS] survival) and harms (relapse and nonrelapse mortality) from included studies. When appropriate, data were pooled using random-effects model.

Results: Four studies (128 patients) were included in analysis. Pooled OS rate was 50% (95% confidence interval [CI], 41-59) for all patients. Among patients who underwent allografting whose disease was in first complete remission (CR1), pooled OS and PFS/DFS rates were 67% (95% CI, 52-80) and 53% (95% CI, 29-76), respectively. For patients who underwent allografting in > CR1, pooled OS and PFS/DFS rates were 7% (95% CI, 0-32) for both outcomes. Relapse rates were higher when reduced-intensity regimens were used (40% [95% CI, 25-56] vs. 18% [95% CI, 7-31]).

Conclusion: This systematic review represents the best available evidence supporting allo-HCT in BPDCN, especially when offered in CR1. Use of myeloablative allo-HCT results in lower pooled relapse rates (18% vs. 40%). A prospective comparative study will be needed to determine the impact of intensity of the conditioning regimen on postallograft relapse.