Staging of multiple myeloma

Multiple myeloma is a heterogeneous disease characterized by proliferation of neoplastic clonal plasma cells and a range of clinical manifestations including skeletal destruction, hypercalcemia, anemia, renal failure, immune suppression, and hyperviscosity syndrome [1]. Outcome of patients with myeloma is very variable with survival ranging from a few months to several years depending on the biology of the disease as well as the health status of the patient, which in turn may be largely affected by disease burden. The heterogeneity of the disease presents a challenge for the patient, clinician as well as the research community. Accurate prediction of the clinical course is important in treatment planning. Many treatment options that have different likelihood of response and carry different levels of risk of toxicity may be available for a given patient. Having a reliable prediction of disease prognosis allows both the patient and physician to choose therapy commensurate with the predicted natural history of the disease. Patients with disease that is expected to have a more aggressive course may be offered, and they may be willing to accept, therapy that offers higher probability of response even if it carries more risks of side effects whereas patients predicted to have slowly progressive disease may be candidates for less aggressive therapy. Availability of a standardized prediction system also allows for comparisons across different clinical trials by providing a means to ensure equivalent patient populations in the trials. Similarly, efficacy of different therapies developed over time can be better compared. An ideal staging system would utilize objective and reproducible factors that are easily obtainable and commonly used in clinical practice. The staging system should be applicable across the spectrum of the disease and segregate patients into roughly equal groups (Table 5.1).