Multiple Myeloma

Myeloma or Multiple myeloma is a type of blood cancer; it affects the plasma cells which are made in your bone marrow.  Myeloma patients make up about 1% of cancer patients in the UK. Myeloma does not exist as a lump like other cancers, but divides within the bone marrow, often replacing the bone marrow cells. It is known as multiple myeloma as it often occurs in more than one area in the body.

Myeloma cancerous cells take the place of important stem cells which are present in the bone marrow. The bone marrow is the factory that makes all of your blood cells, the red blood cells (erythrocytes) which carry oxygen and carbon dioxide around the body, the platelets (thrombocytes) which are involved in clotting and the white blood cells (leucocytes) which help you fight infection. The cells at severely damaged by myeloma would normally go on to become a type white blood cells called plasma cells (originally ß-lymphocytes)which produce proteins known as antibodies to fight infection.

Myeloma occurs due to a genetic mutation in cells, these cells bind to others in the bone marrow (called stromal cells).  This causes the stromal cells to produce a cytokine (chemical messengers) called IL-6 this leads to the uncontrolled growth of the myeloma cells. The cells over-activate osteoclasts which break down the bone and produce growth factors which allow new blood vessels to be made (a process known as angiogenesis) to bring nutrients to the affected region.

Antibodies or immunoglobulins are proteins which are released in the immune response and are specific to the antigens (cell markers) present in disease causing micro-organisms. In myeloma, instead of antibodies, the damaged cells produce paraproteins, which have no use in fighting infection but can thicken the blood and take the place of infection fighting molecules (so reduce immunity).

Myeloma normally occurs in the skull, pelvis, ribs, shoulders and spine (where it can cause spinal cord compression and tingling/numbness of limbs). Some symptoms of myeloma include bone pain, fatigue, bone fractures, anaemia (reduction in oxygen carrying capacity of the blood), hypercalcaemia (excess calcium in the blood as is released by affected bones, could lead to problems with the heart and have an effect on behavior/personality). People with myeloma can also sustain kidney damages
due to paraproteins or a build up of calcium blocking the narrow tubes that are used by the kidneys to filter the blood of toxic waste products, increased fluid intake can help to alleviate these problems. People with myeloma are also very susceptible to infection due the problems with the white blood cells which stimulate an immune response (people on cancer treatments such as chemotherapy are also immunosuppressed so are at a high risk of infection)

Myeloma is a fairly rare disease, and has quite general symptoms which can be associated with other illness. Blood tests showing a low blood count (though this is indicative of several blood conditions) abnormal antibodies/proteins (using a serum protein electrophoresis test and testing immunoglobulin levels), high calcium levels are indicators of myeloma as well as urine tests with paraproteins present. Bone marrow biopsy tests (which are quite painful) are usually used to confirm myeloma if there are too many plasma cells and myeloma cells present.

Treating myeloma involves removing the cancerous cells and treating the symptoms caused by myeloma. Myeloma is not yet curable and will often reoccur several times. All myeloma patients begin with induction treatment of a combination of three myeloma drugs. Suitable patients may go on to have intensive treatment such as high-dose chemotherapy and stem cell transplants, but for some patients, this could be too toxic or dangerous.

Induction treatment includes a chemotherapy drug, a steroid and one of  thalidomide or bortezomib. Chemotherapy drugs include melphalan and cyclophosphamide which are given orally; these
medications are generally well tolerated by patients but side effects include hair loss (due to the effect on dividing cells such as the myeloma cells but also hair and nail cells), nausea and infection. The role of steroids is not entirely clear, but they appear to prevent new myeloma cells from growing and the success of treatment improves the longer steroid treatment continues. Dexamethasone and prednisolone are steroids often used and are usually given orally. Side effects of steroids include indigestion, difficulty sleeping and water retention (so swollen ankles and feet). Bortezomib is a brand new class of anti-cancer medication known as proteasome inhibitors (this means it blocks the

action of a protein called proteasome which removes waste products and recycles others, including cyclins which need to be destroyed in order for the cell to continue to divide) this causes the death of the myeloma cells. Associated side effects include nausea, diarrhoea and fatigue. Thalidomide is a drug usually associated with the birth defects it can cause (discovered when it was prescribed as a drug to act against morning sickness in pregnant women) However, the drug is effective in killing myeloma cells, by preventing the angiogenesis which therefore prevents the development of a blood (and therefore nutrient) supply to the cancerous cells. Thalidomide comes in tablet form and should be taken with food. Obviously, the drug cannot be given to pregnant women and those of a child bearing age should ensure that they use effective contraceptives if on the medication and if not, should also avoid contact with the medication.  Thalidomide can increase the chance of blood clots; so many patients may need to take warfarin to thin their blood. Other side effects include headaches, constipation, skin rashes and numbness in hands and feet.

Intensive treatment includes high-doses of chemotherapy drugs to destroy more myeloma cells, however this can destroy healthy bone marrow severely affecting immunity. To improve this, healthy bone marrow stem cells are transplanted into the patient. These stem cells usually come from the patient (although may come from siblings or even unrelated donors). This treatment requires hospital admittance and a recovery period of several months, so is not recommended for older/frailer patients.

Radiotherapy can be used to treat the cancer by using targeted high-energy radiation. Myeloma is considered to be particularly responsive to radiotherapy. Whole body irradiation can be used for advance myeloma in just two sessions (one session for the top half another for the bottom), but some can be lengthy treatment over several weeks Monday to Friday. It can also relieve bone pain when targeted at weak areas, by reducing the number of cancerous cells, so allowing the bones to repair themselves. Often only one or two radiotherapy sessions are needed to reduce the pain. Radiotherapy can cause nausea and fatigue.

As bone pain is a common symptom of myeloma, patients are likely to be prescribed painkillers; however anti-inflammatory drugs (like ibuprofen) can further damage the kidneys of people with myeloma. Biophosphonates can be given to strengthen bones, reduce hypercalcaemia and reduce bone pain. These drugs can be taken via an IV drip once a month (which lasts 15 minutes to several hours depending on the drug) or in tablet form (which need to be taken more regularly. On this treatment you should drink lots of water in order to remove calcium from the blood. Currently these drugs are undergoing research into their ability to treat myeloma itself. Spinal cord compression can be treated with radiotherapy and steroids are used to reduce the pressure on the spine, though surgery may be needed. This surgery could involve percutaneous vertebroplasty where a ‘cement’ is injected into the vertebrae to stabilise the bone or balloon kyphoplasty where an inflatable bone tamp (which is like a balloon) is inserted into the spine to relieve pressure and return vertebrae to a normal height.  Surgery is usually considered a final option and there is a risk of infection. In other affected bones metal pins or plates may be inserted to provide strength.  A low red blood cell count due to myeloma resulting in anaemia can be treated by blood transfusions and a drug called erythropoietin to encourage red blood cell production.

Steroids and thalidomide are often used for several years as maintenance treatment to prolong the effects of the treatment. However, myeloma can return in which case, patients are often prescribed a similar course of treatment (though not intensive treatment). Bortezomib is only used in the first relapse and only is a response such as a drop by half of abnormal myeloma proteins in the blood. Another drug for relapsed patients (but not those newly diagnosed) is called lenalidomide. Lenalidomide works in a similar way to thalidomide, and can reduce the chance of progression of the cancer to only 20%, but also can reduce numbers of white blood cells (therefore patients even more vulnerable to infection) and number of platelets (increases bruising and bleeding).

As many people diagnosed with myeloma are over 60, and so likely to suffer from several conditions, the average life expectancy after diagnosis is less than 10 years. Over a third of patients will lie at least 5 years and 10% will live for more than 10 years, and recent data shows that myeloma survival rates in the UK are one of the fastest increasing f all cancer types. Although there is no cure for myeloma, various treatments can hold it in remission for many years, and over the last ten years, there has been many new drugs developed and so doubled survival rates. Clinical studies for new medications are ongoing and there is currently research into drugs with fewer side effects and could increase the outlook for patients, improving survival and quality of life.

http://www.macmillan.org.uk/Cancerinformation/Cancertypes/Myeloma/Myeloma.aspx
http://www.myeloma.org.uk/intro-to-myeloma/what-is-myeloma/what-causes-it/
http://www.nhs.uk/Conditions/Multiple-myeloma/Pages/Introduction.aspx