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Monoclonal Gammopathy of Undetermined Significance

Patients with monoclonal gammopathy of undetermined significance (MGUS) have a monoclonal (or myeloma) protein (M protein) in the serum without symptoms or findings of multiple myeloma, macroglobulinemia, amyloidosis, or lymphoma and with less than 10% of plasma cells in the bone marrow.[1,2] Multiple myeloma, other plasma cell dyscrasia, or lymphoma will develop in 12% of patients by 10 years, 25% by 20 years, and 30% by 25 years. Unfortunately, patients who will eventually develop plasma cell malignancy or lymphoma cannot be identified on the basis of the level of M protein, peripheral blood count, type of monoclonal immunoglobulin, percentage of plasma cells in the bone marrow, or levels of normal immunoglobulins. Therefore, all patients with MGUS must be kept under observation to detect increases in M protein levels and development of one of the above malignancies; however, higher levels of initial M protein levels correlate with increased risk of progression to multiple myeloma.[2] In a large retrospective report, the risk of progression at 20 years was 14% for an initial monoclonal protein level of 0.5 g/dL or less, 25% for a level of 1.5 g/dL, 41% for a level of 2.0 g/dL, 49% for a level of 2.5 g/dL, and 64% for a level of 3.0 g/dL.[2]

Current Clinical Trials

Check for U.S. clinical trials from NCI's PDQ Cancer Clinical Trials Registry that are now accepting patients with monoclonal gammopathy of undetermined significance. The list of clinical trials can be further narrowed by location, drug, intervention, and other criteria.

General information about clinical trials is also available from the NCI Web site.

References:

Kyle RA, Rajkumar SV: Monoclonal gammopathy of undetermined significance and smouldering multiple myeloma: emphasis on risk factors for progression. Br J Haematol 139 (5): 730-43, 2007.
Kyle RA, Therneau TM, Rajkumar SV, et al.: A long-term study of prognosis in monoclonal gammopathy of undetermined significance. N Engl J Med 346 (8): 564-9, 2002.

WebMD Public Information from the National Cancer Institute

Last Updated: August 02, 2010

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