Prognostic impact of circulating plasma cells in patients with multiple myeloma: implications for plasma cell leukemia definition

Abstract

The presence of circulating plasma cells in patients with multiple myeloma is considered a marker for highly proliferative disease. In the study herein, the impact of circulating plasma cells assessed by cytology on survival of patients with multiple myeloma was analyzed. Wright-Giemsa stained peripheral blood smears of 482 patients with newly diagnosed myeloma or plasma cell leukemia were reviewed and patients were classified into 4 categories according to the percentage of circulating plasma cells: 0%, 1–4%, 5–20%, and plasma cell leukemia with the following frequencies: 382 (79.2%), 83 (17.2%), 12 (2.5%) and 5 (1.0%), respectively. Median overall survival according to the circulating plasma cells group was 47, 50, 6 and 14 months, respectively. At multivariate analysis, the presence of 5 to 20% circulating plasma cells was associated with a worse overall survival (relative risk 4.9, 95% CI 2.6–9.3) independently of age, creatinine, the Durie-Salmon system stage and the International Staging System (ISS) stage. Patients with ≥5% circulating plasma cells had lower platelet counts (median 86×109/L vs. 214×109/L, P<0.0001) and higher bone marrow plasma cells (median 53% vs. 36%, P=0.004). The presence of ≥5% circulating plasma cells in patients with multiple myeloma has a similar adverse prognostic impact as plasma cell leukemia.

Increased circulating plasma cells detected by flow cytometry predicts poor prognosis in patients with plasma cell myeloma

“…The incidence of PCM patients with cPCs was around 15-20% by morphologic exam of Wright-Giemsa stained PB smear (17,18), and the incidence increased up to 80% with slide based IF (19). The incidence of PCM patients with cPCs was around 15-20% by morphologic exam of Wright-Giemsa stained PB smear (17,18), and the incidence increased up to 80% with slide based IF (19).…”

“…PCs in PB have been detected by various methods and the negative prognostic implication of cPCs has been well established in patients with plasma cell disorders. The incidence of PCM patients with cPCs was around 15-20% by morphologic exam of Wright-Giemsa stained PB smear (17,18), and the incidence increased up to 80% with slide based IF (19). Following development of FC technology, research for cPCs has mainly progressed using this modality.…”

Primary plasma cell leukemia: A case report and review of the literature

“…The current diagnostic definition of PCL is not prospectively studied and delays many from receiving early aggressive management strategies due to underdiagnosis. The presence of 5% circulating clonal plasma cells has been suggested to improve detection . This has been echoed by a recent Mayo Clinic study in December 2018 that showed those diagnosed between 1971 and 2016 with > = 5% circulating plasma cells (CPCs) had much poorer survival outcomes compared with those who did not have CPCs on diagnosis .…”

“…The presence of 5% circulating clonal plasma cells has been suggested to improve detection. 40 This has been echoed by a recent Mayo Clinic study in December 2018 that showed those diagnosed between 1971 and 2016 with > = 5% circulating plasma cells (CPCs) had much poorer survival outcomes compared with those who did not have CPCs on diagnosis. 41 The successful treatment of this patient with VCD and daratumumab may prove an effective induction strategy for similar patients with an aggressive presentation, who are not candidates for AuSCT.…”

Pursuing a Curative Approach in Multiple Myeloma: A Review of New Therapeutic Strategies

“…This approach should incorporate baseline risk evaluation and dynamic risk evaluation (MRD achievement and duration) during treatment (Figure 1). Baseline risk factors such as International Staging System (ISS), cytogenetics, lactate dehydrogenase (LDH) levels [117], extramedullary disease [118], circulating plasma cells [119], TP53 mutations [94], and many others can help define our therapeutic strategy. For instance, the use of double ASCT and long-term treatment with a PI plus IMiDs maintenance could be beneficial in the presence of high-risk cytogenetics [92].…”