Imaging in Stem Cell Transplant and Cell-based Therapy

74

amounts to 0.5–1% per year [ 5 ]. MM is a very heterogeneous malignant disorder
with refractory and relapsing course of disease that can be classified as low and
high­risk [ 6 ]. High­risk MM is characterized by presence of extramedullary disease,
larger than 20% plasma cell in peripheral blood (plasma cell leukemia), unfavorable
genetic alterations (deletion 17p, deletion 1p, gain 1q21, t(14;20), t(14;16)), and
poor clinical outcome and overall survival (OS) [ 6 – 8 ].
The introduction of high­dose (HD) chemotherapy and autologous bone marrow
transplantation (ABMT) 30 years ago has revolutionized the treatment of patients
with MM [ 9 ]. It is general consensus among myeloma experts that HD­chemotherapy
and autologous stem cell transplantation (ASCT) is the backbone for treatment in
newly diagnosed MM patients [ 10 ]. However, in the era of novel, potent anti­
myeloma agents the role of ASCT needs to be redefined. The treatment landscape
has dramatically changed in recent years with the introduction of highly effective

MGUS Multiple Myeloma

Serum M-protein ≥3.0 g/dL

OR

Urine M-protein ≥500 mg/24h

AND / OR

Clonal plasma cells in bone marrow: 10–

60%

Absence of myeloma defining events or

amyloidosis

Clonal plasma cell in bone marrow: ≥10%

OR

Biopsy-proven bony

or extramedullary plasmocytoma

≥1 Myeloma defining events:

• Hypercalcemia: serum calcium >1 mg/dL
  higher than the upper limit of normal or

  
  

  11 mg/dL

  
  

  
  


• Renal insufficiency: creatinine clearance
  <40 mL/min or serum creatinine >2 mg/dL


• Anemia: Hemoglobin >2 g/dL below the
  lower limit of normal range, or hemoglobin
  <10 g/dL


• Bone lesions: ≥1 osteolytic lesion(s) on
  skeletal radiography, CT, or PET-CT
  OR
  ≥1 New myeloma defining biomarkers:


• Clonal plasma cell in bone marrow: ≥60%


• Involved : uninvolved serum free light
  chain ratio ≥100


• 
  

  
  

  1 focal lesions on MRI studies

  
  

  
  

Serum M-protein <3.0 g/dL

Clonal plasma cells in bone marrow: <10%

Absence of myeloma defining events or

amyloidosis

Smoldering Myeloma

No treatment

Fig. 5.1. Diagnostic criteria for multiple myeloma, smoldering myeloma and monoclonal gam­
mopathy of undetermined significance

S. Thanendrarajan and T.K. Garg