Mutiple myeloma is a malignant monoclonal proliferation of plasma cells.
The commonest subclass is IgG (IgG>IgA>IgM)
Incidence is 4 per 100000
Commonest in those in their 70s
Males > females (1.5:1)
Twice as common in those of Afro-Caribbeam descent compared to Caucasian.
Average survival 4 to 6 years
Higher beta 2 microglobulin implies a worse prognosis.
Symptoms:
- osteolytic bone lesions --> backache/pathological fractures
- fatigue due to anaemia
- symptoms of hypercalcaemia
- bacterial infections due to immunoparesis
- renal impairment due to light chains
- symptoms associated with hyperviscosity
However, over 30% of patients are asymptomatic when myeloma is detected.
Investigations:
- Bloods:
- normocytic normochromic anaemia
- rouleaux on blood film
- raised calcium (40%)
- raised urea and creatinine
- raised ESR
- Urine
- Bence Jones proteins (=free serum light chains) in urine (66%)
- XR
- ?pepper pot skull, vertebral collapse
- bone marrow – 10% or more clonal bone marrow plasma cells
The diagnostic criteria for symptomatic myeloma is:
- monoclonal protein band in serum or urine electrophoresis
- increased plasma cells on BM biopsy
- evidence of end organ damage from myeloma
- monoclonal protein band in serum ≥30g/l a nd/or bone marrow clonal plasma cells ≥10%
Treatment:
- supportive of complications
- bisphosphonates to avoid fractures (Zoledronic acid is current preferred))
- transfusions if severe anaemia
- treatment of hypercalcaemia
- chemotherapy:
- younger (<65 yrs) or fit: VAD = vincristine, adriamycin (=doxorubicin), dexamethasone then ASCT (Autologous stem cell transplantation)
- older: CDT or MDT = cyclophosphamide or melphalan with dexamethasone and thalidomide
Cylophosphamide and melphalan are alkylating agents.
Side effects of thalidomide include somnolence, neuropathy, deep venous thrombosis. Risk of DVT is much increased when combined with steroid treatment.
A new medication, Bortezomib, which is a new anticancer drug that works by reversible proteaseome inhibition. It is associated with thrombocytonia and peripheral neuropathy and is currently only recommended for patients who are not appropriate for aggressive therapy and do not tolerate thalidomide.
Complications of myeloma include:
- Hyperviscosity syndrome
- Hyperviscosity syndrome occurs most commonly in IgM myeloma (IgM>IgA>IgG)
- Transfusions should be avoided in hyperviscosity syndrome.
- hypercalcaemia
- spinal cord compression - occurs in 5% at some point
- acute renal failure - 20% at presentation, up to 50% at some point
- treat with at least 3 litres of normal saline daily
- treat precipitating events eg hypercalcaemia, sepsis
- high dose dexamethasone (unless CI) pending initiation of definitive treatment
- AL amyloidosis (15%)
- VTE
Lasted reviewed March 2015
