MGUS Prognosis

Patients with monoclonal gammopathy of undetermined significance (MGUS) have an increased risk of developing a hematologic malignancy, most often multiple myeloma from IgG and IgA MGUS, and other malignant lymphoproliferative disorders from IgM MGUS. A previous large study from the Mayo Clinic of patients in Minnesota with MGUS detected an overall risk of progression of approximately 1% per year (Kyle 2002). This model from the same Minnesota population proposes a risk-stratification model based on serum M-protein concentration, type of paraprotein, and presence of an abnormal serum free kappa:lambda light chain ratio (Rajkumar 2005). This risk-stratification model may be useful in identifying MGUS patients with a high risk of progression as candidates for closer supervision and potential clinical trial strategies. It may also prove useful in identifying patients with a very low risk of malignant transformation and less intensive follow-up (BCSH MGUS Guidelines), although surveillance strategies based on this model require prospective study.