The International Myeloma Working Group’s newly-released consensus recommendations on plasma cell leukemia (PCL), published online ahead of print this month in the journal Leukemia, calls for adjusted diagnostic criteria, clarifies primary PCL response and progression criteria, and advises prompt and intensive induction chemotherapy and bortezomib-based regimens, followed by high-dose therapy plus autologous stem cell transplantation (ASCT), where possible. Bortezomib “will likely become the backbone” of treatment for this rare but aggressive variant of myeloma, the Working Group concludes. Although much remains to be learned about optimal treatments, the Working Group advocates consideration of allogeneic stem cell transplantation for patients younger than 50 with a suitable donor.
PCL is a particularly aggressive form of myeloma, with distinct primary or de novo (pPCL) and secondary variants (sPCL)—“two distinct clinical and biological entities that only share the features of plasma cells circulating in the peripheral blood and an ominous clinical course,” according to the Working Group authors. Rapid detection and treatment are key to maximizing patient survival.
“The diagnosis of PCL needs to be made in a timely manner and immediate therapy initiated,” they emphasize.
Both pPCL and sPCL are associated with very poor prognosis. Up to 70% of cases are pPCL, arising in patients not previously diagnosed with myeloma; it presents more frequently than myeloma with extramedullary involvement, anemia, thrombocytopenia, hypercalcemia, elevated levels of serum β2-microglobulin and lactate dehydrogenase, and functional impairment of the kidneys.1,2 pPCL is more aggressive and involves higher tumor burdens than myeloma, but with fewer lytic bone lesions.1
Patients with pPCL “may present with symptoms due to profound anemia, hypercalcemia, or bleeding diathesis owing to thrombocytopenia,” the authors report. “On physical examination, patients may exhibit a higher prevalence of organomegaly with involvement of the liver, spleen, lymph nodes, pulmonary findings associated with pleural effusions, neurological deficits due to central nervous system involvement, pallor, petechiae, and palpable extramedullary soft-tissue plasmacytomas.”