Research Article

Bone Marrow Plasma Cell Assessment before Peripheral Blood Stem Cell Mobilization in Patients with Multiple Myeloma Undergoing Autologous Stem Cell Transplantation

Table 1

Characteristics of patients and treatment.

All patients (N = 106) (%)BMPCs before PBSC mobilizationP value
<5% (N = 73)≥5% (N = 33)

Baseline characteristics
 Age, years, median (range) 56 (33–65) 56 (34–65) 56 (33–65) ns
 Patient gender (M/F)59 (56)/47 (44)39 (53)/34 (47)20 (61)/13 (39)ns
 Serum M proteinns
  Light chain30 (28)20 (28)10 (30)
  Other than light chain76 (72)53 (72)23 (70)
 Stage at diagnosisns
  IIA 6 (6)6 (8)0 (0)
  IIIA/B 100 (94) 67 (92) 33 (100)
 Cytogenetics*ns
  Standard risk88 (83)63 (86)25 (76)
  High risk18 (17) 10 (14) 8 (24)
 BMPCs at diagnosis, %, median (range)39 (3–90)38 (3–88)42.3 (8–90)ns
 Myeloma bone disease on plain radiographs, yes/no81 (76)/25 (24)58 (80)/15 (20)23 (70)/10 (30)ns
 Serum calcium at diagnosis, mg/dL, median (range)8.9 (6.8–16.2)8.9 (6.8–15.7)9.0 (7.4–16.2)ns
 Serum creatinine at diagnosis, mg/dL, median (range)0.9 (0.4–8.3)0.9 (0.4–8.3)0.9 (0.5–5.6)ns
β2-microglobulin at diagnosis, mg/mL, median (range)3.5 (0.2–41.4)3.5 (0.2–41.4)3.8 (1.6–36.0)ns
 Hemoglobin at diagnosis, g/dL, median (range)9.8 (6.0–17.2)9.8 (6.0–17.2)9.5 (6.5–14.8)ns
 Serum lactate dehydrogenase at diagnosis, U/L, median (range)374 (81–1054)389 (165–1054)361 (81–889)ns

Treatment and outcomes
 Induction therapy0.039
  Bortezomib ± dexamethasone51 (48)36 (49)15 (46)
  Bortezomib + thalidomide + dexamethasone12 (11.5)8 (11)4 (12)
  Thalidomide + dexamethasone31 (29)17 (23)14 (42)
  High-dose dexa-based regimen12 (11.5)12 (17)0 (0)
 Duration from diagnosis to ASCT, months, median (range)6.7 (2.9–15.6)6.9 (2.9–15.6)6.1 (3.9–15.3)ns
 Maintenance therapy after ASCT0.742
  Yes73 (69)51 (70)22 (67)
  Thalidomide50 (47)35 (48)15 (46)
  Bortezomib or Lenalidomide8 (8)3 (4)5 (15)
  Prednisolone15 (14)13 (18)2 (6)
  No33 (31)22 (30)11 (33)
 Serologic response before PBSC mobilization<0.001
  CR 39 (37)35 (48)4 (12)
  VGPR 38 (36)25 (34)13 (39.5)
  PR 25 (23) 12 (17) 13 (39.5)
  SD4 (4)1 (1)3 (9)
 Serologic response after PBSC mobilization<0.001
  CR 47 (44)41 (56)6 (18)
  VGPR 36 (34)22 (30)14 (42)
  PR 20 (19) 10 (14) 10 (30)
  SD3 (3)0 (0)3 (9)

ASCT: autologous stem cell transplantation; BMPCs: bone marrow plasma cells; CR: complete response; ns: not significant; PBSC: peripheral blood stem cell; PR: partial response; SD: stable disease; VGPR: very good partial response.
*High risk cytogenetics is defined as hypodiploidy or deletion 13 on conventional cytogenetics or presence of , , and del(17p) on fluorescent in  situ hybridization and/or conventional cytogenetics. All other cytogenetic abnormalities were considered standard risk.