Beta-2-microglobulin is an independent predictor of progression in asymptomatic multiple myeloma.
BACKGROUND
Although serum beta-2 microglobulin (B2M) represents a key variable for symptomatic multiple myeloma (MM) prognostication, its role in predicting the risk of progression of asymptomatic MM to symptomatic disease has not been explored.


METHODS
This study was bases on a consecutive series of 148 patients with asymptomatic MM and explored the cumulative probability of progression to symptomatic MM as the primary endpoint.


RESULTS
In univariate analysis, a serum B2M level >2.5 mg/L was associated with an increased probability of disease progression (5-year risk, 64.5%; P < .001) along with serum monoclonal component (sMC) (P < .001), urinary monoclonal component (uMC) (P < .001), and bone marrow plasma cells (BMPCs) (P < .001). In multivariate analysis, serum B2M was selected as an independent predictor of progression (hazard ratio, 3.30; P = .002). Serum B2M was combined with sMC, uMC, and BMPC to create a risk-stratification model based on 4 groups with different risk of progression: very low (5-year risk, 0%), low-intermediate (5-year risk, 19.6%), high-intermediate (5-year risk, 60.7%), and high (5-year risk, 80.7%). The model that included serum B2M along with sMC, uMC, and BMPC was able to predict disease progression better than the model that was based on sMC, uMC, and BMPC without serum B2M (C statistics, 0.760 vs 0.726).


CONCLUSIONS
The current results indicated that 1) serum B2M is an independent predictor of asymptomatic MM progression, and 2) serum B2M adds prognostic information when combined with the most widely used prognosticators of asymptomatic MM progression.
Rossi
Davide
D
Division of Hematology, Department of Clinical and Experimental Medicine, Amedeo Avogadro University of Eastern Piedmont and Maggiore della Carita Hospital, Novara, Italy. rossidav@med.munipmn.it
Fangazio
Marco
M
De Paoli
Lorenzo
L
Puma
Alessia
A
Riccomagno
Paola
P
Pinto
Valeria
V
Zigrossi
Paola
P
Ramponi
Antonio
A
Monga
Guido
G
Gaidano
Gianluca
G
D000368:Aged; D018450:Disease Progression; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009101:Multiple Myeloma / Q000097:blood*; D011379:Prognosis; D012307:Risk Factors; D001613:beta 2-Microglobulin / Q000032:analysis*
D001613:beta 2-Microglobulin