Evaluation of serum beta 2-microglobulin as a prognostic indicator in myelomatosis.

Serum beta 2-microglobulin (beta 2-m) is frequently increased in patients with myelomatosis. The possibility that it could provide a biochemical indicator of prognosis was tested in a group of 129 patients from 3 centres, all serum analyses being carried out in one laboratory by radioimmunoassay. A strong association between the pretreatment serum beta 2-m level and survival was demonstrated, the data for the 2 main subgroups being very similar. In further detailed analyses of 64 patients, serum beta 2-m proved to be a stronger indicator of prognosis than current "standard" clinical and laboratory data, including stage determined by the method of Durie and Salmon and the combination of haemoglobin level and blood urea. The association between serum beta 2-m and survival remained close after treatment as indicated by the findings at one year. The serum beta 2-m in myeloma reflects the tumour mass and also reduced glomerular filtration when renal failure supervenes. It is concluded that the serum beta 2-m is a powerful prognostic indicator in myelomatosis and of considerable value in the investigation of patients with the disease.