- Is a type of cancer that begins in the bone marrow. It affects the plasma cells.
- Belongs to a spectrum of disorders referred to as "plasma cell dyscrasia."
- Has several forms:
- Multiple myeloma is most common: More than 90 percent of people with myeloma have this type. Multiple myeloma affects several different areas of the body.
- Plasmacytoma - only one site of myeloma cells evident in the body, such as in the bone, skin, muscle, or lung.
- Localized myeloma - a few neighboring sites evident.
- Extramedullary myeloma - involvement of tissue other than bone marrow, such as skin, muscles or lungs.
Doctors divide myeloma into groups that describe how rapidly or slowly the disease is progressing:
- Asymptomatic or smoldering myeloma progresses slowly and has no symptoms even though the patient has the disease.
- Symptomatic myeloma has related symptoms such as anemia, kidney damage and bone disease.
Click here to access myeloma statistics.
What You Should Know
- Hematologists and oncologists are specialists who treat people who have myeloma or other types of blood cancer.
- Treatment outcomes vary widely among patients; results depend on many individual factors.
What You Should Do
- Talk with your doctor about your diagnostic tests and what the results mean
- Talk with your doctor about all your treatment options and the results you can expect from treatment.
- Ask your doctor whether a clinical trial is a good treatment option for you.
How Does Myeloma Develop?
Myeloma starts with one or more changes to the DNA of a single stem cell in the bone marrow.
- Stem cells form blood cells (white cells, red cells and platelets).
Myeloma develops in a white cell called a B lymphocyte (B cell).
- Some B lymphocytes mature into plasma cells, which make antibodies.
- In myeloma, an injury to a B cell's DNA causes an abnormal change that can start the transformation of a normal plasma cell into a cancerous cell.
The cancerous cells multiply at a faster rate than normal cells and don't die off when they should. They eventually crowd out functioning cells. Most of the cancerous cells are confined to the marrow, but sometimes they circulate in the blood. If not treated, the cancerous cells can:
- Crowd out functioning white cells, and the immune system can't guard against infection effectively
- Secrete high levels of protein in the blood and urine, which can lead to kidney damage
- Build up in bone, causing it to weaken, which can lead to bone pain and fractures.
Doctors don't know why some cells become myeloma cells and others don't. For most people who have myeloma, there are no obvious reasons why they developed the disease.
There are some factors that may increase the risk of developing myeloma, including:
- Age - Most people who develop myeloma are over age 50 years. Few cases of myeloma occur in people younger than 40.
- Sex - More men develop myeloma than women.
- Race - African Americans are nearly twice as likely to develop myeloma as are whites (Caucasians).
- Medical History - People who have a prior history of the diagnosis MGUS (monoclonal gammopathy of unknown significance).
- Environment - Some studies are showing a link between the development of myeloma and smoking, radiation, or exposure to certain kinds of chemicals such as pesticides, fertilizers and Agent Orange (see A Risk for Vietnam Veteransbelow).
- Obesity - New research suggests that people who are obese have a higher incidence of myeloma.
A Risk for Vietnam Veterans
The National Academy of Sciences suspects there may be a link between myeloma and exposure to herbicides like Agent Orange used during the Vietnam conflict from 1961 to 1971. If you have myeloma and think you may have been exposed to Agent Orange or other herbicides, you may be entitled to disability compensation from the U.S. Department of Veterans Affairs. For more information, visit the U.S. Department of Veterans Affairs website.
Source: Myeloma. Reviewed by Melissa Alsina, MD