Myeloma

• 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 neighbouring 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 develops when a plasma cell is mutated (changed). 

• Plasma cells are made from B cells, a type of white blood cell that is present in the bone marrow. Healthy plasma cells are part of the immune system, and make proteins called “antibodies,” which help fight infection.

The mutated plasma cell (the myeloma cell) multiplies, and, if untreated, these cells continue to grow in the marrow. They crowd out the healthy plasma cells and the normal stem cells in the bone marrow that form the white blood cells, red blood cells and platelets. 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.

Risk Factors

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. Fewer cases of myeloma occur in people younger than 40.
• Sex - More men develop myeloma than women.
• Race - African Canadians 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 radiation or exposure to certain kinds of chemicals such as pesticides, fertilizers and Agent Orange.
• Obesity - New research suggests that people who are obese have a higher incidence of myeloma.

Source: Myeloma. Reviewed by Melissa Alsina, MD