An Introduction to Multiple Myeloma

Myeloma is a cancer of plasma cells that begins in the bone marrow. A single mass of myeloma cells is called a solitary plasmacytoma, which is most often found in the bones but can also be found in soft tissue (called an extramedullary plasmacytoma). Multiple plasmacytomas are referred to as multiple myeloma.

In the bone marrow, blood stem cells develop into three elements: red cells (which carry oxygen throughout the body), platelets (which help stop bleeding by causing the blood to clot) and white cells (which fight infection and perform other duties associated with the immune system). These cells are suspended in plasma, the liquid part of the blood, which also contains vitamins, minerals, proteins, hormones, antibodies and other chemicals. In response to bacteria or viruses entering the body, white blood cells, called plasma cells, produce antibodies that target particular bacteria and viruses for destruction. Multiple myeloma is a cancer characterized by plasma cells that multiply too fast and don’t shut off reproduction when they should. Instead of producing antibodies that help fight infection, myeloma cells develop essentially useless antibodies called “monoclonal” or “M” protein.

It is unknown what causes plasma cells to become myeloma cells. It happens when a white blood cell hits a glitch in the genetic mechanism that programs its transition into a plasma cell. Instead of a normal plasma cell, a myeloma cell results. Eventually, these myeloma cells start crowding out other types of blood cells in the bone marrow, including normal plasma cells. Like weeds in an untended garden, this overgrowth impedes the immune system and disrupts the continual process of bone remodeling.

Multiple myeloma is relatively rare—the lifetime risk of getting multiple myeloma is 1 in 159, according to the American Cancer Society. The vast majority of patients are older than 65. For reasons that are unknown, myeloma occurs more frequently in some racial groups, such as African-Americans.

There is no cure for myeloma, but treatment advances over the past decade have enabled many patients to live longer, healthier lives with the disease. Less than a generation ago, the odds of someone surviving five years after diagnosis was about 1 in 10. Today, the odds of surviving five years are about 4 in 10, and doctors expect survival time to increase even more in the future. It’s possible for patients to live many years with a disease on a slow simmer that does not pose an immediate threat to health. The longer survival means that about 100,000 Americans are currently living with multiple myeloma, according to the International Myeloma Foundation.

From "A Patient's Guide to Multiple Myeloma," published in the Winter 2011 issue of CURE. Download the full guide here.