Low and high risk monoclonal gammopathy of undetermined signifikance: analysis outcomes of RMG registry Czech Myeloma Group for practice
Abstract
The primary end point was to estimate the cumulative risk of hematologic disorders occurring during the follow-up of our cohort. The secondary end points were: to validate known clinical models suggested by the Mayo Clinic group and the Spanish PETHEMA group for the risk of progression from MGUS to MM or related malignancies and to establish a new risk model by the Czech Myeloma Group (CMG model) with better prediction of low-risk MGUS group. 1887 MGUS persons were followed with median 4 years.
Malignancies developed in 8.6 % (162/1887) cases; MM occurred in 77.2 % (125/162) of persons. The risk of progression was 1.5 % at 1 year, 7.6 % at 5 years and 16.5 % at 10 years after diagnosis.
The key predictors factors of progression were as follows: age GREATER-THAN OR EQUAL TO 69 years, serum M- protein concentrationGREATER-THAN OR EQUAL TO 15 g/L, bone marrow plasma cells > 5 %, pathological sFLC ratio (1.65), immunoparesis of polyclonal immunoglobulins and levels of serum hemoglobin at baseline < 120 g/L. Distribution of MGUS persons according to risk groups based on the Mayo Clinic model confirmed predictive power of Mayo Clinic model based on our data although isotype of M- protein was not found as independent predictor.
In the large cohort of MGUS persons, we confirmed validity of previously considered clinical models for the riskof progression from MGUS to MM by the Mayo Clinic group and the Spanish PETHEMA group (model used for SMM). New CMG model for the risk of progression from MGUS to MM or related malignancies was established with an advantage for better identification of MGUS persons at low risk (87 % of persons with risk of progression below 10 % in 5 years) as well as few persons at the highest risk of progression.