Myeloma

The normal job of plasma cells is to produce antibodies or immunoglobulin as part of an immune response to infection. Myelomatous plasma cells also produce antibody and often in large amounts. However the myeloma cells produce one specific antibody unique to the tumour. This can be measured and is referred to as a paraprotein or M band. Antibodies themselves are made of two parts; heavy chains and light chains. The heavy chains are usually Ig or immunogolubin G or IgA but there are others. The light chains are either kappa or lambda. Individual patient’s myeloma is often referred to by the type of paraprotein produced so someone may have a IgG kappa or and IgA lambda myeloma. Sometimes myeloma cells get things wrong and fail to make a complete antibody but do manage to produce the light chain. This is referred to as light chain myeloma. The light chains are small enough to pass through the kidneys. When detected in the urine they are referred to a Bence Jones Protein. Not infrequently a paraprotein may be picked up on a routine blood tests and this is one of the ways myeloma comes to light.  

It is important to be aware that not all paraproteins are due to myeloma indeed the majority are not.  The finding of an isolated paraprotein or MGUS ( monoclonal gammopathy of uncertain significance) is very  common and increases with age. Around 5% or people over 70 will have a detectable paraprotein but very few will have or develop myeloma. 

Unlike lymphoma, myeloma rarely presents with lymph gland enlargement or soft tissue lumps. It typically presents with cancerous plasma cells involving the bone marrow. This can cause a variety of problems from low blood counts and anaemia to increased susceptibility to infection. Myeloma can also cause damage to be surrounding bone and this can be a serious problem resulting in bone pain or bone fractures and a high level of calcium in the blood.  Myeloma can also cause serious kidney damage particularly in people with light chain myeloma.  

If myeloma is suspected we would arrange for a number of tests to establish the diagnosis and to assess the severity of the disease. These may include blood and urine tests and a scan (usually CT) of the bones to establish whether there is any bone damage. A bone marrow biopsy is often required to establish the diagnosis and the extent of the disease. It can also provide valuable information about the genetics of the disease. 

There have been some very real improvements in the treatment of myeloma over the last 7 to 8 years and this disease is now more controllable than it has ever been. The mainstay of treatment now is based on three drugs , thalidomide, bortezomib and lenalidomide. The consensus among myeloma experts is that combination therapy with three drugs is best with the addition of drugs such as cyclophosphamide or melphalan and steroids such as prednisolone or dexamethasone. There also remains a role for autologous (self) stem cell transplantation in some people. Myeloma cannot be cured with current treatments but for most people a remission is achieved and a good quality of life maintained both on and off treatment.