Objective: To review biologic factors that may be useful in determining prognosis in patients with myeloma.
Design: The currently available clinical variables and staging systems were assessed for their predictive value in myeloma, and newly proposed prognostic factors were summarized.
Results: Because some patients with myeloma may potentially benefit by new, more intensive therapies such as stem cell transplantation or may have prolonged survival with standard therapy, determining factors that would distinguish such patients is important. Independent prognostic factors such as the plasma cell labeling index and beta 2-microglobulin have repeatedly outperformed other prognostic clinical variables and can be combined into a system that identifies poor, intermediate, and good prognostic groups of patients with myeloma. New factors are needed to improve on the predictive value of these two variables. Studies of the biologic features of myelomas have led to the discovery of soluble interleukin 6 receptor (sIL 6R) in the serum. sIL 6R enhances the myeloma cell response to interleukin 6, a central growth factor that affects myeloma cell proliferation. Preliminary studies by the Eastern Cooperative Oncology Group show that sIL 6R predicts survival independent of the plasma cell labeling index and beta 2-microglobulin. Other proposed independent prognostic factors include cytokines and their soluble receptors, regulatory T cells, circulating myeloma cells, myeloma cell precursors, and markers of proliferation, apoptosis, and drug resistance.
Conclusion: Because of wide variation in duration of survival, the prognosis of patients with myeloma, a fatal bone marrow plasma cell neoplasm, cannot yet be adequately predicted. Better prognostic factors are needed for stratification in clinical trials, counseling of patients, and designing of new therapeutic trials.