Serum beta2 microglobulin and survival duration in multiple myeloma: a simple reliable marker for staging

Previous reports have shown serum beta2 microglobulin (SB2M) to be a reliable marker for evaluation of presenting tumour mass, response to chemotherapy and prognosis of patients with multiple myeloma (MM). In the current study, SB2M was evaluated and correlated by bivariate and multivariate regression analyses with the main presenting clinical features, response to chemotherapy and survival duration of 115 untreated myeloma patients. In the bivariate analysis, there was a clear correlation between SB2M and myeloma stage (P = 0.002). Other interesting correlations were between SB2M and creatinine values (P less than 0.001), SB2M and the likelihood of having lambda subtype (P less than 0.001), high SB2M and high uric acid (P less than 0.036), high SB2M and a low haemoglobin (P less than 0.001). In the multivariate regression analyses, SB2M alone completely substituted for the effect of initial staging and gave a very reliable fit for survival prediction. Particularly noteworthy was the dramatic difference in survival duration observed between patients with a high pre-treatment SB2M (greater than 6 micrograms/ml) and those with low SB2M: 26 months versus 52 months (P less than 0.0001). We conclude that SB2M is the major determinant of survival in MM and can be used alone for effective pretreatment stratification of myeloma patients.