Monoclonal Gammopathy of Undetermined Significance (MGUS)

Freelite enables risk stratification of MGUS Patients *

An abnormal serum free light chain ratio has been identified as an important, independent risk factor for progression of MGUS to myeloma or related malignancies.

Monoclonal gammopathy of undetermined significance is an asymptomatic condition that occurs in 1% of the population over 50 years of age, and >3% over 70 years of age. It is traditionally associated with the presence of a low level monoclonal band (<20g/L) in the serum, usually no light chains in the urine and <5% plasma cells in the bone marrow. Monitoring of MGUS patients is essential as a significant percentage (approximately 1% per annum) progress to develop Multiple Myeloma or related malignant condition.

Risk stratification

In a recent study of 1148 MGUS patients seen at the Mayo clinic between 1960 and 1994, an abnormal serum kappa/ lambda ratio was identified as a major independent risk factor for progression of MGUS to myeloma or a related malignancy1.
This risk stratification identified a low risk subset (40%) with a remarkable small life-time risk of progression, only 2% over 20 years.

Risk stratification
Risk group Numbers of Patients Absolute risk of progression at 20 years**
LOW
(serum M protein <1.5 gm/dL, IgG subtype, Normal FLC ratio)
449 2%
LOW INTERMEDIATE RISK
(Any 1 factor abnormal)
420 10%
HIGH INTERMEDIATE RISK
(Any 2 factors abnormal)
226 18%
HIGH RISK
(All 3 factors abnormal)
53 27%

** accounting for death as a competing risk

This research was originally published in Blood: Rajkumar et al. Serum free light chain ratio is an independent risk factor for progression in monoclonal gammopathy of undetermined significance. Blood 2005; 106:812-817 ©2005 The American Society of Hematology.

MGUS

Risk of progression of MGUS to myeloma or related disorder using a risk-stratification model that incorporates the FLC ratio and the size and type of the serum monoclonal protein. The top curve illustrates risk of progression with time in patients with all 3 risk factors, namely an abnormal serum kappa-lambda FLC ratio (< 0.26 or >1.65), a high serum monoclonal protein level (> 15 g/L), and non-IgG MGUS; the second gives the risk of progression in patients with any 2 of these risk factors; the third curve illustrates the risk of progression with one of these risk factors; the bottom curve is the risk of progression for patients with none of the risk factors.

This research was originally published in Blood: Rajkumar et al. Serum free light chain ratio is an independent risk factor for progression in monoclonal gammopathy of undetermined significance. Blood 2005; 106:812-817 ©2005 The American Society of Hematology.

 

Freelite and MGUS patient management

MGUS

Effect of increasingly abnormal FLC ratio on the relative risk of progression of monoclonal gammopathy of undetermined significance to multiple myeloma or related disorder. This figure illustrates that as the serum kappa-lambda FLC ratio becomes increasingly abnormal, the risk of progression increases.

This research was originally published in Blood: Rajkumar et al. Serum free light chain ratio is an independent risk factor for progression in monoclonal gammopathy of undetermined significance. Blood 2005; 106:812-817 ©2005 The American Society of Hematology.

Freelite can contribute to the management of your MGUS patients.

* In the USA diagnostic use of this product is restricted to those stated in the product insert

References

  1. S.Vincent Rajkumar, Robert A. Kyle, Terry M. Therneau, L. Joseph Melton III, Arthur R. Bradwell, Raynell J. Clark, Dirk R. Larson, Matthew F. Plevak, Angela Dispenzieri, Jerry A. Katzmann.
    "Serum free light chain ratio is an independent risk factor for progression in monoclonal gammopathy of undetermined significance (MGUS)"
    Blood 2005;106;3: 812-817

    Reference: MKG275 Quantity: