Evaluation of the Impact of the Update SMM Criteria on the Natural History of SMM to Establish New Recommendations.

In 2014, the International Myeloma Working Group (IMWG) proposed a revised classification of multiple myeloma (MM) and smoldering myeloma (SMM). Since the new definition of SMM proposed excludes "ultra-high risk SMM", the evolution profile of SMM will change. Therefore, investigators need to update their knowledge of SMM to optimize the management of patients. This project is expected to describe more precisely the new landscape of SMM.

The results will help to establish new recommendations for the standard care of SMM and especially for defining accurate follow-up and risk stratifying.

Inclusion criteria

• Age ≥ 18 years.
• SMM defined by IMWG 2014 criteria

• Serum monoclonal protein (IgG or IgA) ≥30 g/L and/or urinary monoclonal protein ≥500 mg per 24 h and/or clonal bone marrow plasma cells 10-60%
• Absence of myeloma defining events or amyloidosis
• Diagnosed less than 1 year before the inclusion
• Able and willing to give valid written informed consent. Patients must give written informed consent (IC) in accordance with institutional and local guidelines.

Exclusion criteria

• Previous antimyeloma treatment including bisphosphonates
• Second Primary Malignancy and/or auto-immune disease treated by immunosuppressive drugs.
• Evidence of end organ damage that can be attributed to the underlying SMM:

• Hypercalcaemia: serum calcium >0.25 mmol/L (>10 mg/L) higher than the upper limit of normal or >2.75 mmol/L (>110 mg/L)
• Renal insufficiency: creatinine clearance <40 mL/min or serum creatinine >177 μmol/L (>20 mg/L)
• Anaemia: haemoglobin value of >2 g/dL below the lower limit of normal, or a haemoglobin value <10 g/dL
• Bone lesions: one or more osteolytic lesions on skeletal radiography, CT, or Positron Emission Tomography-Computed Tomography (PET-CT)
• Presence of one of the following biomarkers of malignancy:

• Clonal bone marrow plasmocytosis ≥60%
• Involved/uninvolved serum Free Light Chain (FLC) ratio ≥ 100 (The involved free light chain must be ≥100 mg/L)
• Presence of one or more focal lesions on MRI studies (each focal lesion must be 5 mm or more in size)
• History of malignancy other than SMM within 3 years before inclusion
• Amyloidosis
• POEMS syndrome
• Contraindication to MRI
• Pregnancy
• Nursing mother
• Legally protected adults (under judicial protection, guardianship, or supervision)