Analysis of Outcomes of Patients with Blastic Plasmacytoid Dendritic Cell Neoplasm
Authors: Pemmaraju Naveen , Thomas Deborah , Kantarjian Hagop M. , Cortes Jorge E. , Manning John T , Medeiros L. Jeffrey , O'Brien Susan , Daver Naval G. , Nazha Aziz , Pierce Sherry A. , Garcia-Manero Guillermo , Jabbour Elias J. , Faderl Stefan 
Published: October 2019

Abstract
Abstract 3554

Background:
Blastic plasmacytoid dendritic cell neoplasm (BPDCN), formerly known as CD4 + CD56 + hematodermic tumor or blastic NK cell lymphoma, is a rare and aggressive hematologic malignancy. Little is known about the outcome of patients (pts) with BPDCN.

Methods:
We performed a retrospective review of pts age ≥ 18 years of age with a pathological diagnosis of BPDCN.

Results:
19 pts, diagnosed and treated at our institution between October 1998-January 2011, were identified. There were 16 (84%) males and 3 females with a median age of 56 years (range 20–86 years). Bone marrow (BM) was involved in 13 (68%), skin in 13 (68%), lymph nodes in 5 (26%), and 1 (5%) pt each had disease involving the brain, CSF, uterus/ovary, elbow soft tissue, and pleural fluid. The tumor immunophenotype was: CD4+ (17/17), CD56+ (16/17), and TCL-1+ (9/9). Conventional cytogenetics in10 pts showed: diploid (5 pts), complex karyotype (4 pts), and del (12p13) (1pt). The median complete blood count was: WBC 6.7 × 109/L (1.7–76.5), Hb 13.3 g/dL (8.3–17.0), and platelet count 107 × 109/L (44–294). The median BM blast count was 40% (0–77). Therapy for these pts was: 13 (68%) first-line therapy with Hyper-CVAD alternating with high-dose methotrexate (MTX) and cytarabine (in 1 pt following one cycle of CHOP), 4 (21%) CHOP, 1 (5%) oral MTX (1), and 1 (5%) interferon-based therapy. 4 (21%) pts received radiation (XRT) as part of their therapy. The median follow-up time was 13 months (5–25 mo). The median number of chemotherapy regimens was 1 (1–6). Complete remission (CR) was achieved in 12 pts. The median CR1: 18 mo (4–39 mo). Median overall survival (OS) was 29 mo (1–44 mo). 14 (74%) pts died, with the most common cause of death being multi-organ failure (8 pts).
For 6 (32%) pts without BM involvement at diagnosis; all 6 had skin involvement. Comparison of pts with BM involvement versus those with skin only showed no differences. For pts with BM disease, the median OS, and median CR1 were 23 mo (1–44 mo), 21 mo (4–39 mo), respectively. For pts with skin only disease, the median OS and median CR1 were 29 mo (8–31 mo), 18 mo (8–23 mo), respectively, p=0.82 (OS), p=0.78 (CR1).
6 pts (32%) received stem cell transplant (SCT) (3 autologous, 2 allogeneic,1 cord blood). The median OS for pts receiving SCT (n=6) was 31 mo (10–40 mo) versus a median OS for non-SCT group (n=13) of 29 mo (1–44), p= 0.82.
13 pts (68%) received HCVAD as part of first line therapy: the median OS was 29 mo (1–44 mo) and median CR1: 21 mo (4–39 mo). Eleven (92%) of 12 of these pts achieved CR1; 1 pt did not achieve CR1 (died, pneumonia, day 15).

Conclusions:
Despite intensive multi-agent chemotherapy and SCT, response rates are low and survival is short for pts with BPDCN. A better understanding of the biologic basis of this disease and novel treatment approaches are needed.

Disclosures:
No relevant conflicts of interest to declare.