Primary plasma cell leukemia and autologous stem cell transplantation

Primary plasma cell leukemia is a rare disorder accounting for less than 5% of malignant plasma cell diseases. It has a poor prognosis compared to multiple myeloma, with a median survival of 8-12 months. The results of conventional therapy are disappointing though autologous stem cell transplantation may improve survival.

A retrospective analysis was undertaken of the European Group for Blood and Marrow Transplantation experience of 272 patients with plasma cell leukemia and 20844 with multiple myeloma undergoing first autologous transplantation between 1980 and 2006. All patients were reported to the European Group for Blood and Marrow Transplantation registry using MED-A (limited data) or MED-B (extensive data) forms. All patients were included regardless of availability of complete data.

There was no difference in type of graft or use of total body irradiation between patients with plasma cell leukemia and multiple myeloma, but the group with plasma cell leukemia was transplanted earlier after diagnosis (6.0 versus 7.7 months, P=0.000). Patients with plasma cell leukemia were more likely to enter complete remission after transplantation but their overall survival (25.7 months, 95% confidence interval 19.5-31.9 months) was inferior to that of patients with multiple myeloma (62.3 months, 95% confidence interval 60.4-64.3 months) (P=0.000), due to the short duration of their post-transplant response and increased non-relapse-related mortality.

This largest study ever reported on plasma cell leukemia suggests that autologous transplantation can improve outcome, although results are markedly inferior to those achieved in patients with multiple myeloma, highlighting the need for novel approaches to this aggressive disorder.