Multiple myeloma is cancer that starts in the plasma cells in bone marrow. Bone marrow is the soft, spongy tissue found inside most bones. It helps make blood cells.
Plasma cells help your body fight infection by producing proteins called antibodies. With multiple myeloma, plasma cells grow out of control in the bone marrow and form tumors in the areas of solid bone. The growth of these bone tumors weakens the solid bones and also makes it harder for the bone marrow to make healthy blood cells and platelets
The exact cause of multiple myeloma is not clear. Past treatment with radiation therapy increases the risk of this type of cancer. Multiple myeloma mainly affects older adults.
Multiple myeloma most commonly causes a low red blood cell count (anemia), which can lead to fatigue and shortness of breath. It can also cause low white blood cell count, which makes you more likely to get infections. Multiple myeloma can also cause low platelet count, which can lead to abnormal bleeding.
As the cancer cells grow in the bone marrow, you may have bone or back pain, most often in the ribs or back.
The cancer cells can weaken bones. You may develop broken bones (bone fractures) just from doing normal activities.
If cancer grows in the spine bones, pressure on the nerves may result. This can lead to numbness or weakness of the arms or legs.
Exams and Tests
Blood tests can help diagnose this disease. These tests include:
Total protein level
Kidney function blood tests
Complete blood count (CBC)
Blood and urine tests to identify proteins, or antibodies (immunofixation)
Blood tests to quickly and accurately measure the specific level of certain proteins called immunoglobulins (nephelometry)
Bone x-rays may show fractures or hollowed out areas of bone. If your doctor suspects this type of cancer, a bone marrow biopsy will be performed.
Bone density testing may show bone loss.
People who have mild disease or in whom the diagnosis is not certain are often not treated. Instead they are closely monitored. Some people have a slow-developing form of multiple myeloma (smoldering myeloma) that takes years to cause symptoms.
Chemotherapy is usually used to treat multiple myeloma. It is most often given to prevent complications of multiple myeloma, such as bone fractures and kidney damage.
High levels of calcium in the blood, which can be very dangerous
Increased chances for infection, especially in the lungs
Weakness or loss of movement due to tumor pressing on spinal cord
When to Contact a Medical Professional
Call your doctor if you have multiple myeloma and you develop an infection, or numbness, loss of movement, or loss of sensation.
National Cancer Institute: PDQ Plasma Cell Neoplasms (Including Multiple Myeloma) Treatment. Bethesda, Md: National Cancer Institute. Date last modified: March 12, 2014. Available at: http://www.cancer.gov/cancertopics/pdq/treatment/myeloma/healthprofessional. Accessed: March 23, 2014.
National Comprehensive Cancer Network. NCCN Clinical Practice Guidelines in Oncology: Multiple Myeloma. Version 2.2014. Available at: http://www.nccn.org/professionals/physician_gls/pdf/myeloma.pdf. Accessed: March 23, 2014.
Rajkumar SV, Dispenzieri A. Multiple myeloma and related disorders. In: Niederhuber JE, Armitage JO, Doroshow JH, et al., eds. Abeloff's Clinical Oncology. 5th ed. Philadelphia, Pa: Elsevier Churchill Livingstone; 2013:chap 104.
Yi-Bin Chen, MD, Leukemia/Bone Marrow Transplant Program, Massachusetts General Hospital. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.