Marcadores pronósticos en pacientes con gammapatía monoclonal de significado incierto

Objective

The assessment of prognostic biomarkers in monoclonal gammopathies of uncertain significance (MGUS) requires using large cohorts and long follow-ups, due to the low rate of conversion to multiple myeloma (MM). The aim of this article is to develop a model that allows smaller cohorts and shorter follow-ups to be used with high reliability.

Patients and methods

A total of 64 MGUS patients were studied and followed-up prospectively for 6 ± 0.24 years. Patients were classified as evolving or non-evolving, depending on whether the monoclonal protein levels increased or not over time. The risk of conversion to MM was tested based on these phenotypes, and whether the factors that predict conversion to MM are also associated with the appearance of an evolving phenotype.

Results

Eleven patients showed an evolving phenotype, and 53 a non-evolving one. All patients who converted to MM previously showed evolving phenotype (P = .003). At diagnosis, evolving phenotype associated with monoclonal gammopathies of IgA isotype (27 vs. 9%), monoclonal IgG levels above 1,500 mg/dl (P = .007, OR 9.8) and altered kappa/lambda ratios (P = .001, OR 11.7).

Conclusions

Risk factors for developing an evolving phenotype in MGUS patients are the same as those already described for the development of MM. These data show the validity of the evolving/non-evolving model to study markers to predict the outcome of MGUS patients, and confirm the role of the levels of monoclonal IgG and the light chains ratio in the prognosis of this disease.