Primary plasma cell leukemia in Latin America: demographic, clinical, and prognostic characteristics. A study of GELAMM group.

Primary plasma cell leukemia (pPCL) is an infrequent and aggressive plasma cell disorder. The prognosis is still very poor, and the optimal treatment remains to be established. A retrospective, multicentric, international observational study was performed. Patients from 9 countries of Latin America (LATAM) with a diagnosis of pPCL between 2012 and 2020 were included. 72 patients were included. Treatment was based on thalidomide in 15%, proteasome inhibitors (PI)-based triplets in 38% and chemotherapy plus IMIDs and/or PI in 29%. The mortality rate at 3 months was 30%. The median overall survival (OS) was 18 months. In the multivariate analysis, frontline PI-based triplets, chemotherapy plus IMIDs and/or PI therapy, and maintenance were independent factors of better OS. In conclusion, the OS of pPCL is still poor in LATAM, with high early mortality. PI triplets, chemotherapy plus IMIDs, and/or PI and maintenance therapy were associated with improved survival.

[Primary plasma cell leukemia. Report of five cases]. / Leucemia de células plasmáticas primaria: experiencia en un hospital público chileno.

BACKGROUND: Primary plasma cell leukemia (pPCL) is uncommon, aggressive and has a different biology than multiple myeloma (MM). AIM: To report the features of patients with pPCL. MATERIAL AND METHODS: Review of databases of the Hematology Department and the Hematology laboratory. RESULTS: Of 178 patients with monoclonal gammopathies, five (2.8%) patients aged 33 to 64 years (three females) had a pPCL. The mean hemoglobin was 7.3 g/dL, the mean white blood cell count was 52,500/mm3, with 58% plasma cells, and the mean platelet count was 83,600/mm3. The mean bone marrow infiltration was 89%, LDH was 2,003 IU/L, serum calcium was 13 mg/dL, and creatinine 1.5 mg/dL. Two patients had bone lesions. Three were IgG, one IgA lambda and one lambda light chain. CD20 was positive in one, CD56 was negative in all and CD117 was negative in 3 cases. By conventional cytogenetic analysis, two had a complex karyotype. By Fluorescence in situ Hybridization, one was positive for TP53 and another for t (11; 14). One patient did not receive any treatment, three patients received VTD PACE and one CTD. None underwent transplant. Three patients are alive. The mean survival was 14 months. CONCLUSIONS: These patients with pPCL were younger and had a more aggressive clinical outcome than in multiple myeloma.

Leucemia de células plasmáticas primaria: experiencia en un hospital público chileno / Primary plasma cell leukemia: report of five cases

Background: Primary plasma cell leukemia (pPCL) is uncommon, aggressive and has a different biology than multiple myeloma (MM). Aim: To report the features of patients with pPCL. Material and Methods: Review of databases of the Hematology Department and the Hematology laboratory. Results: Of 178 patients with monoclonal gammopathies, five (2.8%) patients aged 33 to 64 years (three females) had a pPCL. The mean hemoglobin was 7.3 g/dL, the mean white blood cell count was 52,500/mm3, with 58% plasma cells, and the mean platelet count was 83,600/mm3. The mean bone marrow infiltration was 89%, LDH was 2,003 IU/L, serum calcium was 13 mg/dL, and creatinine 1.5 mg/dL. Two patients had bone lesions. Three were IgG, one IgA lambda and one lambda light chain. CD20 was positive in one, CD56 was negative in all and CD117 was negative in 3 cases. By conventional cytogenetic analysis, two had a complex karyotype. By Fluorescence in situ Hybridization, one was positive for TP53 and another for t (11; 14). One patient did not receive any treatment, three patients received VTD PACE and one CTD. None underwent transplant. Three patients are alive. The mean survival was 14 months. Conclusions: These patients with pPCL were younger and had a more aggressive clinical outcome than in multiple myeloma.

Plasma cell leukemia.

Plasma cell leukemia (PCL) is a rare, yet aggressive plasma cell (PC) neoplasm, variant of multiple myeloma (MM), characterized by high levels of PCs circulating in the peripheral blood. PCL can either originate de novo (primary PCL) or as a secondary leukemic transformation of MM (secondary PCL). Presenting signs and symptoms are similar to those seen in MM such as renal insufficiency, hypercalcemia, lytic bone lesions, anemia, and thrombocytopenia, but can also include hepatomegaly and splenomegaly. The diagnostic evaluation of a patient with suspected PCL should include a review of the peripheral blood smear, bone marrow aspiration and biopsy, serum protein electrophoresis (SPEP) with immunofixation, and protein electrophoresis of an aliquot from a 24h urine collection (UPEP). The diagnosis is made when a monoclonal population of PCs is present in the peripheral blood with an absolute PC count exceeding 2000/µL and PC comprising 20% or more of the peripheral blood white cells. The prognosis of PCL is poor with a median survival of 7 to 11 months. Survival is even shorter (2 to 7 months) when PCL occurs in the context of refractory or relapsing MM. There have been no prospective randomized trials investigating the treatment of PCL. Recommendations are primarily based upon data from small retrospective series, case reports, and extrapolation of data from patients with MM. In general, patients are treated with induction therapy followed by hematopoietic cell transplantation (HCT) in those who are appropriate candidates for this approach. The best induction regimen for PCL is not known and there is great variability in clinical practice. Newer agents that are being incorporated into frontline and salvage therapy for MM have also demonstrated activity in PCL such as Immunomodulatory agents and the use of bortezomib with different combinations.