Therapeutic implications of myeloma staging.

Clinical staging, such as with the Durie-Salmon clinical staging method, remains the most easily usable available method to classify patients with untreated multiple myeloma. However, for the development of new treatment strategies and comparison with prior results, new and powerful prognostic factors are now available. Serum beta 2 microglobulin alone represents the most reliable prognostic factor in multiple myeloma. Beta 2 microglobulin alone allows simple and reproducible classification of patients into low grade myeloma with low serum beta 2 microglobulin versus high grade myeloma with high serum beta 2 microglobulin. Plasma cell labelling index is an additional factor which allows identification of patients with MGUS as well as subclassification of patients with low serum beta 2 microglobulin into those with relatively better or worse prognosis. For each grade of myeloma young (less than 63 years of age) patients have a slightly better survival. Independently of serum beta 2 microglobulin and labelling index, DNA content values allow the identification of a subset of patients with biclonal or hypodiploid tumors and high grade disease. New or more sophisticated methods for evaluating myeloma cells such as by immunophenotyping or assessment of multi drug resistance enable the development of specific approaches to treatment in individual cases. It should also prove possible to identify patients especially suitable for newer biologic agents such as alfa interferon, G or G-MCSF and the various interleukins.