Precursor to myeloma

can appear as a tumor and/or as an area of bone loss. In either case, this is called a lesion. The presence of myeloma cells within the bone marrow can lead to other medical problems within and outside the bone marrow microenvironment.

Many highly effective therapies are approved for treatment of myeloma by the United States Food and Drug Administration (FDA), the European Medicines Agency (EMA), and by other regulatory agencies. Numerous clinical trials are currently taking place around the world, adding more promising therapies to the growing list of treatment options.

Many myeloma patients lead full and productive lives for years, even decades, after diagnosis. Survival and quality of life of myeloma patients are improving steadily. Learning about myeloma and understanding how it is treated can help patients and their loved ones reduce their anxiety, gain a sense of control, and make it easier to come to terms with the diagnosis.

The earliest stage of myeloma is a benign condition called monoclonal gammopathy of undetermined significance (MGUS). People with MGUS must be monitored carefully for a possible change in their status. If the level of M-protein remains stable and there are no other health changes, the time between visits to your hematologist and/or oncologist can be extended.

All myeloma patients have MGUS before they progress to myeloma, but only 20% of people diagnosed with MGUS eventually develop myeloma. The risk of progression from MGUS to myeloma is 1% per year.

The stage between MGUS and active myeloma is called smoldering multiple myeloma (SMM). It is characterized by a higher level of M-protein

Table 1. Definitions of MGUS and SMM

NAME DEFINITION

MGUS • Monoclonal protein present but usually < 3.0 g/dL • No CRAB features or other indicators of active myeloma • Bone marrow monoclonal plasma cells < 10% SMM • Higher level of disease than MGUS: serum M-protein can be > 3.0 g/dL and/or bone marrow plasma cells between 10% and 60%, but • No CRAB features or other indicators of active myeloma