How would you approach a patient with smoldering myeloma that has a quickly rising and very high M-spike (6 g/dL range)?

The level is very high and worrisome for tumor lysis syndrome and cytokines related symptoms.

I would do a bone marrow biopsy first and check free light chain assay. This may confirm the diagnosis of symptomatic myeloma. Also bone imaging study to find any lesions.

Once you decide to treat I would ...