Understanding Multiple Myeloma

The simplest way to define multiple myeloma is to call it a cancer of the blood. Yet, it's a complicated disease that starts in your blood but also gradually affects your bones and other parts of your body in many different ways.

To best understand multiple myeloma, let's start where the disease starts, in your blood.

Blood contains cells that are produced in the bone marrow, particularly the big bones of the body, such as the skull, pelvis, ribs, and sternum, as well as the long bones of the legs (femur) and arms (humerus).

 

How Plasma Cells Become Myeloma Cells

Typically, plasma cells are made in an orderly and regulated manner. In fact, as cells are being made, each step is "inspected" to ensure that it has been accurately completed. Think of these cellular inspections like building inspectors: if a step has been completed, the OK is given to move forward. If the cell does not pass inspection, development is stopped until the cellular construction workers correct the mistake. Or, if the problem cannot be fixed the cell may be destroyed through a process of natural cell death called apoptosis.

Cancer, however, is able to bypass this inspection process. In fact, cancer exploits the cellular activities to make more cancer cells and ensure its own survival. Therefore, the once controlled production of plasma cells becomes uncontrolled, leading to the overproduction of abnormal plasma cells. These abnormal plasma cells are now called myeloma cells.

Multiple Myeloma Exists on a Spectrum

The progression from a healthy state to multiple myeloma is thought to be a multi-step process. That is, there are several phases that one may pass through before experiencing the signs and symptoms of multiple myeloma.

Three stages of the disease have been described:

• One may start with an "idle" or indolent stage
• An overt stage where there is an increase in the presence of myeloma cells
• A malignant stage called multiple myeloma

In the indolent phase, a person may have one of two different conditions – either monoclonal gammopathy of undetermined significance (MGUS) or smoldering myeloma. In addition, not everyone will progress from one phase to the next. Many people may live with MGUS without ever experiencing symptoms, needing treatment, or progressing to multiple myeloma.

The Multi-step Process of Multiple Myeloma

The idle or indolent phase of multiple myeloma may present itself as one of two different conditions, either monoclonal gammopathy of undetermined significance (MGUS) or smoldering myeloma. Though these conditions share some similar characteristics, they also differ in some important ways.

MGUS may be diagnosed when the presence of M-proteins is detected in the blood, but there are no signs of damage to the organs or bones of the body and there are no other signs or symptoms.

In rare cases, MGUS may evolve into multiple myeloma. The risk of progression of MGUS to multiple myeloma is about 1% per year. For most people, however, MGUS is not dangerous and does not require treatment. Healthcare providers typically take a "watch and wait" approach, and those with MGUS are evaluated regularly to monitor for changes in their M-protein levels and to see if other symptoms have developed. The exact monitoring schedule may vary. Please consult your healthcare team.

Like MGUS, smoldering myeloma, does not produce the typical signs and symptoms of disease and is therefore not treated. Monitoring is performed regularly so that if the disease does become symptomatic, it can be treated. The key difference between MGUS and smoldering myeloma is that the risk of progressing to symptomatic multiple myeloma is higher with smoldering myeloma. The risk of progression from smoldering myeloma to symptomatic multiple myeloma is about 10% to 20% per year.