Figure 1.

Definition of relapse and indication for treatment. Since MM is an incurable disease, almost all patients experience at least one or more relapses over the course of their disease. It is of great importance to define the right time point to restart or change therapy. The CRAB criteria as well as the IMWG criteria, representing defined biochemical markers of relevance for disease outcome, indicate the need for antimyeloma treatment. If a myeloma patient does not present with typical symptoms or if an increase in biochemical markers is not significant enough, therapy is not imminent; instead, close monitoring of the patient and the decisive diagnostics every 1–2 months should follow. Abbreviations: CRAB criteria = hypercalcemia, renal failure, anemia, bone lesions, FLC = free light chain (monoclonal immunoglobulin light chain), IMWG = international myeloma working group, M-protein = abnormal antibody/monoclonal proliferation of plasma cells, ULN = upper limit of normal.