A malignant proliferation of plasma cells derived from a single clone, with multifocal involvement of the skeleton.
1,115 Aussies diagnosed every year Risk increases w. age : 80% are > 60 y.o. Men > women Black 2x > white Familial link (4x increased risk) 1% of all US cancers, 10% of haemotological cancers
Cause is unknown, however there is evidence for genetic issues; 11q14 and 17p13 deletions (serious) 11q abnormalities T(11;14)(q13;q32), cyclin D1 (cell cycle regulatory gene) (less serious) T(4;14)(p16;q32) heavy chain gene and tyrosine kinase receptor controls cell proliferation Mys, ras, p53 and Rb-1 mutations
Plasma cell attaches to bone marrow stromal cell (handy because…) Monoclonal Ig (M component) is produced; potentially with excess heavy/light chains (urine) Bone destruction (↑ RANKL on OB ↑ OC act., inhibition of OB) IL-6, IGF-1 the main players
Radiograph and lab results 24hr urine to find Bence-Jones bodies Electrophoresis to determine monoclonal Ig/light chains X-rays of osteolytic lesions: require bone marrow examination to confirm.
Some lymphomas and leukaemias (CLL) can also produce M components.
Systemic treatment + symptomatic treatment Cytotoxic agents (proteasome inhibitors) Combination chemo: alters myeloma and stromal cell interaction. Inhibits angiogenesis Bisphosphonates bone and Ca Transplant: prolongs but no cure Radiotherapy for bone pain
Median survival 4-6 years Multiple bony lesions 6-12 months Death usually due to either renal failure or infection
Plasmacytoma Localised myeloma Have the potential to spread. Easier to treat if found in soft tissue. Monoclonal Gammopathy of Uncertain Significance (MGUS) Same genetic abnormalities as MM Asymptommatic w. elevated M components. Progression to MM ~1%. Unpredictable.
Robbins and Cotran, pp 609-611 Harrisons, pp 701-706 Underwood, pp 667-669 Leukaemia association of Australia Up to Date