Prognostic factors and staging in multiple myeloma: a reappraisal.

To assess the important factors in the prognosis and staging of multiple myeloma (MM), we have correlated the presenting clinical features of 147 previously untreated patients with MM with the survival duration using multiple regression analyses. We have included the three major available myeloma-staging systems (MSS), ie, Durie-Salmon (DS), Medical Research Council (MRC), and Merlini-Waldenström-Jayakar (MWJ), plus two new variables related to disease activity: the serum beta 2-microglobulin level (S beta 2M) and the instantaneous rate of bone resorption. Our study confirms the validity of the three MSS in the prediction of survival duration, with a slight but significant advantage for the DS MSS. Among single variables, S beta 2M was the most powerful indicator of prognosis (P less than .0001), serum albumin level being the only variable adding to this significantly (P = .02). Of major interest, S beta 2M alone was a better indicator than MRC and MWJMSS. Finally, S beta 2M and the serum albumin level, variables not included in the three MSS, were better indicators than the classical DS MSS and could be combined simply to give a very powerful system of stratification.