Epidemiology and Clinicopathology of Hepatosplenic T-Cell Lymphoma (HSTCL): Analysis of a Pooled Database

Introduction:

HSTCL is a rare and rapidly progressive extranodal T-cell lymphoma. It accounts to for 1-2% of all T/NK cell lymphomas. Afflicting adolescents and younger adults, HSTCL commonly presents with constitutional symptoms, cytopenias, and hepatosplenomegaly. Up to a third of all the reported cases arise within a clinical context of immunosuppression. This analysis was conducted to update and expand our existing knowledge of this rare disease.

Methods:

In order to study the demographic characteristics, cytogenetic and molecular signatures, therapeutic interventions, survival, and prognostic factors, we compiled a pooled database of 360 cases. Kaplan-Meier survival curves were constructed. Cox proportional-hazards model and Log-rank tests were used to assess the influence of demographic and clinicopathology factors on overall survival (OS).

Results:

A total of 360 patients with confirmed HSTCL were identified. The median age was 30 (0.8-86) years with a peak incidence between ages 13 and 26. There is male predominance with M:F ratio of 2.6 in the whole group, 6 in the immunosuppressed, 2.2 in γδ, and 1.2 αβ. HSTCL with TCRαβ tended to be more CD5+, CD8+, and CD57+. More than 90% presented with constitutional symptoms and had bone marrow involvement. Median overall survival of the whole group was 12 months. The median duration of symptoms to diagnosis is 2 months. The median time from immunosuppression to diagnosis is 5.3 years. Sex, age, jaundice, autoimmune hemolytic anemia, hemophagocytosis, and bone marrow involvement did not affect OS. Furthermore, i7 and/or +8 and TCR type did not impact OS. Compared to no treatment, combination chemotherapy and auto and allo stem cell transplant (SCT) were statistically superior with a median OS of 1, 9, 34, and 30 months respectively. While OS of combination chemotherapy was inferior to that of SCT, there was no significant difference between auto and allo SCT. Immunosuppression adversely impacted OS in the whole group (HR:0.40, p<0.0001) and among the SCT subgroup (HR:0.38, p=0.06). There was no difference between immunosuppression with and without TNFα inhibitors. The quality of response prior to transplant also seemed to impact outcome though it did not reach statistical significance (p=0.07) with OS of 15, 30, and 44 months for none/transient, response less than CR, and CR respectively. Splenectomy improved survival in the whole group (HR:0.66; 95%CI 0.47-0.93). Further analysis revealed that splenectomy impacted survival in the context of combination chemotherapy but not SCT.

Conclusions:

This study presents an updated epidemiologic and clinicopathologic data from a pooled cohort of patients with HSTCL. It identifies the impact of immunosuppression, quality of response, treatment modalities as well as splenectomy on OS.