Multiple Myeloma: Diagnostic Features and Treatment
Diagnostic Features
Multiple myeloma diagnosis requires a combination of serum/urine protein studies, imaging, and bone marrow analysis to identify clonal plasma cells and end-organ damage 1, 2.
Clinical Presentation
Patients commonly present with:
- Bone pain (79% have osteolytic lesions at diagnosis)
- Anemia (73% at presentation)
- Renal impairment (19% have acute kidney injury)
- Hypercalcemia
- Fatigue and weight loss
- Some patients remain asymptomatic 2
Essential Diagnostic Workup
The initial evaluation must include 1, 2:
Laboratory Studies:
- Complete blood count (assess for anemia)
- Comprehensive metabolic panel with serum creatinine (renal function)
- Serum calcium level (hypercalcemia)
- Serum protein electrophoresis with immunofixation
- Serum free light chain assay (critical for diagnosis)
- 24-hour urine protein electrophoresis
- Serum β2-microglobulin, albumin, and lactate dehydrogenase (for staging)
Imaging:
- Full-body skeletal imaging with CT, PET-CT, or MRI (not plain radiographs alone)
- Radiography of symptomatic bony sites initially acceptable
Bone Marrow Analysis:
- Bone marrow biopsy with fluorescence in situ hybridization (FISH) for genetic abnormalities: t(4;14), del(17p), t(14;16)
Risk Stratification
The Revised International Staging System combines β2-microglobulin, albumin, lactate dehydrogenase, and FISH results to predict survival. Stage I patients (28% at diagnosis) have 82% 5-year survival, while high-risk genetic features [del(17p), t(4;14), t(14;16)] significantly worsen prognosis 2.
Treatment Approach
Newly Diagnosed Multiple Myeloma
For transplant-eligible patients (<70 years without significant comorbidities), the standard of care is quadruplet induction therapy with DaraVRd or IsaVRd, followed by autologous stem cell transplantation, then maintenance with daratumumab plus lenalidomide 3.
Transplant-Eligible Patients (<70 years, no major comorbidities)
Induction Therapy (4-6 cycles):
- First choice: DaraVRd (daratumumab + bortezomib + lenalidomide + dexamethasone) or IsaVRd (isatuximab + bortezomib + lenalidomide + dexamethasone) - these quadruplets provide the best risk-benefit profile 3
- Alternative: DaraVTd (daratumumab + bortezomib + thalidomide + dexamethasone) 3
- If quadruplets unavailable: VRd (bortezomib + lenalidomide + dexamethasone) - median PFS 41 months versus historical 8.5 months without therapy 3, 2
Stem Cell Collection:
- Perform after 3-4 induction cycles 3
Autologous Stem Cell Transplantation:
- Conditioning with high-dose melphalan 200 mg/m² 3
- Tandem ASCT should be considered for:
- Genetically defined high-risk disease [del(17p), t(4;14), t(14;16)]
- All patients who received bortezomib-dexamethasone-cyclophosphamide induction 3
Consolidation:
- If only 4 cycles of DaraVRd induction given, consider 2 cycles DaraVRd consolidation 3
Maintenance Therapy:
- Daratumumab + lenalidomide is the new standard of care based on PERSEUS trial PFS results 3
- Previously, lenalidomide alone was standard 3
Transplant-Ineligible Patients
For patients ineligible for transplant with IMWG Frailty Score <2 and age <80 years, IsaVRd or DaraVRd are the new standard regimens 3.
Treatment selection based on frailty:
IMWG Frailty Score <2, Age <80:
- IsaVRd or DaraVRd (pending EMA approval at time of guideline) 3
All Transplant-Ineligible Patients (especially IMWG FS ≥1):
- DaraRd (daratumumab + lenalidomide + dexamethasone) 3
IMWG Frailty Score ≥2:
- Consider dexamethasone-sparing strategy (DaraR) - daratumumab + lenalidomide without dexamethasone 3
If Above Options Unavailable:
- DaraVMP (daratumumab + bortezomib + melphalan + prednisone) or VRd 3
Relapsed/Refractory Multiple Myeloma
For patients with one prior line of therapy who are lenalidomide-sensitive or lenalidomide-naïve, BelaVd (belantamab mafodotin + bortezomib + dexamethasone) is the new standard of care, demonstrating superior PFS (36.6 vs 13.4 months) and OS (74% vs 60% at 36 months) compared to DaraVd 3.
After First-Line Therapy
The DREAMM-7 trial established BelaVd as superior to DaraVd:
- Median PFS: 36.6 months (BelaVd) vs 13.4 months (DaraVd); HR 0.41, P<0.001
- 36-month OS: 74% vs 60%; HR 0.58, P<0.001
- Important caveat: Ocular toxicities occur in 79% (vs 29% with DaraVd), but 87% of visual acuity changes resolve with dose modifications 3
- Pending formal regulatory approval at time of guideline publication 3
Treatment Selection Principles
Second-line regimens depend on 3, 4:
- Refractoriness status to prior drug classes (proteasome inhibitors, immunomodulators, anti-CD38 antibodies)
- Efficacy and toxicity of previous regimens
- Patient comorbidities and age
Multiple options exist including second-generation proteasome inhibitors, immunomodulators, monoclonal antibodies, CAR T-cell therapy, bispecific antibodies, selinexor, and venetoclax for specific genetic subsets 4.
Supportive Care
All patients require:
- Bisphosphonates or denosumab for bone disease management 1
- Venous thromboembolism prophylaxis (especially with immunomodulatory agents) 1
- Management of anemia, renal impairment, and hypercalcemia as needed
Key Clinical Pitfalls
Common mistakes to avoid:
- Using plain radiographs alone for skeletal survey - CT, PET-CT, or MRI are required for adequate sensitivity 1, 2
- Failing to obtain FISH testing for risk stratification - this directly impacts treatment decisions (tandem transplant consideration) 3, 2
- Delaying oncology referral when initial workup suggests myeloma - early specialist involvement improves outcomes 1
- Omitting serum free light chain assay - essential for diagnosis and monitoring 1, 2
- Not considering ocular monitoring when using belantamab mafodotin - requires proactive dose modification protocols 3