Multiple Myeloma / Plasmacytoma           

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myeloma in the bone marrow
Multiple Myeloma is a disease where one of the normal white cells goes bad and mutates and becomes a malignant cell. The white cell that goes bad is the plasma cell, which is normally involved in making antibodies to fight infection.

Once the plasma cell becomes malignant it may no longer make appropriate antibodies which leaves the patient prone to infections or the malignant plasma cells may produce large quantities of abnormal proteins (M spike globulin) that can clog up the blood and create problems (such as blood clots or kidney problems).

The abnormal plasma cells may overgrow the normal cells in the bone marrow and cause anemia and other blood problems, similar to leukemia.The abnormal cells can weaken or damage the bone and cause fractures and bone pain.

So some patients with myeloma have blood problems (anemia, infections, protein damage to the kidneys.) Other patients are primarily affected with bone problems (fractures, bone pain or abnormal calcium levels in the blood.) If the cancer is found in only one bone it is called a solitary plasma cell tumor of the bone (go here).

See stage and newer stage here. Read the NIH booklet or the NCI patient page, the ASCO site, or a recent symposium, recent update (2007) from the ACS here.

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Normal plasma cells help protect the body from germs and other harmful substances.
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Myeloma cell (abnormal plasma cell) making M proteins

Multiple myeloma is a systemic malignancy of plasma cells that is highly treatable but rarely curable. It is potentially curable when it presents as a solitary plasmacytoma of bone or as an extramedullary plasmacytoma. It is critical to determine if this is an isolated plasmacytoma or if the patients already has multiple myeloma (see testing.)

The median survival in the prechemotherapy era for myeloma was only about 7 months. After the introduction of chemotherapy, prognosis improved significantly with median survival of 24 to 30 months and a 10-year survival of 3%. Multiple myeloma is a widespread disease and generally treated with chemotherapy.

Occasionally low dose radiation is used to treat painful bone lesions. Low dose of 15-20Gy are effective in over 90% of the cases in relieving pain (complete response rates in the 65-71% and only 6% requiring retreatment

The classification and incidence for symptomatic plasma cell neoplasia: a. primarily affecting bones , i. multiple myeloma 94% ii. solitary plasmacytoma 3% and b. extramedullary plasmacytoma 3%

 
Plasmacytomas are isolated lesions that respond well to radiation.These usually occur in the bone, nasopharynx, tonsils, or paranasal sinuses. The recommended dose is higher (40-50Gy) and survival is longer than patients with myeloma. These lesions can occur in the bone (solitary plasmacytoma of the bone SPB) or in other parts of the body (like the head and neck area, called extramedullary plasmacytoma or EMP.) Patients with plasmacytoma often develop myeloma at a later date but there is no evidence that the early use of chemotherapy will prevent that. Some data from the literature:
Type of Plasmacytoma Response  to radiation Median Survival Convert  to Myeloma
solitary in bone (SPB) 88 - 96% 17 - 156 months 46 - 56%
extramedullary  (EMP) 83 - 96% 69 - 124 months 8 - 36%