Multiple myeloma (plasma cell myeloma) is a malignant blood disease that originates from a plasma cell clone that has developed from bone marrow B cells and undergone a malignant change. Plasma cells are found in the blood and bone marrow. This cancer does not usually form a distinct tumor; instead, cancerous cells are present everywhere in the bone marrow. Multiple myeloma may form round cancer foci of varying sizes in the bones, destroying normal bone tissue. Such a cancer focus may involve a risk of bone fracture. The disease may also cause osteoporosis (increased bone fragility). A solid tumor, plasmacytoma, located outside the bones may sometimes be associated with multiple myeloma. Sometimes there may be several plasmacytomas. Typically, multiple myeloma patients are 50 to 70 years of age at the time of diagnosis.
According to current knowledge, multiple myeloma is incurable. However, with current treatments, remission can often be achieved, symptoms removed and the patient’s quality of life improved. In recent years, new treatments have considerably prolonged multiple myeloma patients’ survival compared with the situation 10 years ago. The disease has become more like a chronic condition that can be treated when it comes back.
Risk of disease
The cause of multiple myeloma or preventive factors are not known. Before the onset of multiple myeloma, some patients may carry an abnormal protein (M component) in their blood for some time, even for decades. The presence of such an M component is a risk factor for multiple myeloma.
Symptoms of multiple myeloma vary. The first symptom may be fatigue or a severe inflammatory disease, resulting from anaemia. Sometimes, renal insufficiency is the first symptom of the disease. The most common symptom is bone pain, usually in a vertebra. Skeletal changes are most commonly found in vertebrae, ribs, skull and pelvis and the long bones of the limbs. Bones may become fractured spontaneously or as a result of a minor injury. Back pain may be caused by a vertebral compression fracture. Paralysis symptoms may be associated with the condition if spinal stenosis is present.
Calcium released from bones can lead to an elevated calcium content of the blood (hypercalcaemia), which together with the M component in blood can damage the kidneys. Anaemia is also a common finding in multiple myeloma. the erythrocyte sedimentation rate (ESR) is usually considerably elevated. If multiple myeloma has progressed to the second stage, in which treatment is necessary, symptoms usually result from anaemia, renal insufficiency, hypercalcaemia or bone pain.
Multiple myeloma is often found by chance, when looking for the cause of a high ESR or anaemia. The diagnosis is based on bone marrow findings and the detection of paraprotein (M component). A bone marrow sample, blood and urine tests and X-rays of the bones are needed for the diagnosis and analysis of the nature of the disease.
If the amount of disease is low, the calcium content of blood is normal, there are no skeletal changes and the kidneys are functioning normally, the disease can be monitored without treatment. In this case, the disease is called smoldering (asymptomatic) multiple myeloma. It only requires regular monitoring of the patient’s condition. Too early treatment has been found to cause unnecessary adverse effects without prolonged survival.
It is recommended to start treatment if the patient is clearly experiencing symptoms or there are findings such as skeletal changes or renal insufficiency. Today, combinations of different medicines are used, and the treatment is individually planned, taking into account factors such as the patient’s age and other diseases. The most common treatment regime is high-dose cortisone therapy combined with other medicines, including various chemotherapeutic agents and the new multiple myeloma medicines bortezomib and thalidomide or its derivative lenalidomide.
Various supportive treatments play an important role in the treatment of multiple myeloma. Strong painkillers are used for skeletal pain, as well as radiotherapy, when necessary. Bones are treated with bone-strengthening medicines. Exercise is important for the strengthening of bones. Infections are prevented using various antimicrobials.
When treating a physically fit patient under 70 years of age, the plan usually is to eventually administer intensive treatment supported by a transplantation of the patient’s own blood stem cells (autologous stem cell transplantation). This therapy is the final stage of treatment, once the patient has been administered the other treatments described above.
Nearly all pharmacotherapies for multiple myeloma can be administered at home or the outpatient clinic. The treatments usually take several months. During the course of treatment, the patient’s condition and response to treatment are closely monitored. The most common monitoring method is the analysis of the M component from blood samples. Treatments are usually effective in getting the disease well under control and even into remission. When the disease makes significant progress, treatments are restarted.
Allogeneic stem cell transplantation may be used for the treatment of young patients with a poor prognosis. However, this treatment does not come into question for most multiple myeloma patients.
A solitary plasmacytoma is treated with radiotherapy only. This requires that actual multiple myeloma is not detected in the bone marrow.