Blastic Plasmacytoid Dendritic Cell Neoplasm Descriptors and Clinicopathologic Determinants of Survival: Analysis of a Pooled Database

Background:

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare and aggressive hematologic malignancy with a propensity for cutaneous involvement. This disorder has gone through many reiterations over the years, being classified initially as a blastic NK-cell lymphoma, then a subset of AML, and finally recognized as a unique myeloid neoplasm. However, due to the poor understanding and the rarity of the disease, varied treatment approaches have historically been implemented, and no optimal data or guidelines for managing BPDCN are available. Therefore, we conducted this pooled database analysis to identify the prognostic factors, clinicopathological characteristics, and therapeutic strategies that influence survival in this disease.

Methods:

To study the demographic characteristics, molecular and immunohistochemical signatures, therapeutic interventions, survival, and prognostic factors, we compiled a pooled database of 273 cases that fit the diagnostic criteria for BPDCN. Kaplan-Meier survival curves were constructed. Cox proportional hazards model and Log-rank tests were used to assess the influence of demographic and clinicopathologic factors on overall survival (OS).

Results:

A total of 273 patients with confirmed BPDCN were identified. The median age was 61.5. There was a male preponderance with M:F of 2.4. The median duration of symptoms before diagnosis was 5 months. Eighty-one percent of patients presented with skin lesions, 65% of which were disseminated. Involvement of Lymph nodes (LN), bone marrow (BM), spleen, peripheral blood, and CNS occurred in 62%, 73%, 55%, 71%, and 57%. Constitutional symptoms were reported in 13%. The median OS and DFS of the whole group were 16 and 13 months, respectively. Patients younger than 60 had better median OS (30 vs. 10 months, p < 0.0001). The involvement of LN (p = 0.03), BM (p = 0.007), spleen (p = 0.02), and peripheral blood (p = 0.01) was associated with worse OS. Furthermore, disseminated skin involvement had worse OS than focal (p = 0.001). Though CNS involvement, presence of constitutional symptoms, elevated LDH, and TdT negative status had numerically worse OS, it did not reach statistical significance. Sex did not impact OS. Compared to no treatment, non-dose-intense chemotherapy, dose-intense chemotherapy, and stem cell transplant had incrementally superior OS (3 vs. 10 vs. 22 vs. 66 months, p < 0.0001). Patients who attained CR as their best response also had a superior median OS (26 vs. 5 months, p < 0.0001).

Conclusions:

This study presents updated clinicopathologic data from a large, pooled cohort of patients with BPDCN. It identifies age, organ involvement, type of therapy, and quality of response to treatment as critical determinants of OS.