Hi Multibilly,
I believe there are currently two main approaches to classifying the "risk" of smoldering myeloma patients.
One is from the Mayo Clinic and the other is from the Spanish "PETHEMA" myeloma group.
This article describes the two approaches:
http://asheducationbook.hematologylibrary.org/content/2010/1/295.full(Go to the section labeled "Risk of Progression to Multiple Myeloma".)
Both approaches define a set of criteria that create a scoring system. If none of the criteria apply to you, your score is zero. If one of the factors applies to you, your score is one. Etc.
The Mayo Clinic system has three criteria. The article described them as follows: "For SMM patients, the following features are considered to be adverse risk factors: ≥3 g/dL M-protein, an FLC ratio outside the reference range of 0.125 to 8, and ≥10% bone marrow plasma cells. At 5 years of follow-up, SMM patients with all three risk factors have, on average, a cumulative risk of multiple myeloma progression of 76% (median time-to-progression [TTP] was 1.9 years); for patients with two or one risk factors, the corresponding risk was 51% (median TTP, 5.1 years) and 25% (median TTP, 10 years), respectively."
The description of the PETHEMA criteria is a bit harder to understand. Or at least it was for me. There are two factors. The first is whether 95 percent or more of the bone marrow plasma cells are considered "aberrant" (not normal) based on "multiparametric flow cytometry of bone marrow aspirates." The second criteria is whether you have at least one immunoglobulin (Ig) level that is lower than the normal range; if you do, you have what is called "immunoparesis."
The Spanish group found that the risk of progression from smoldering to active myeloma at 5 years was 4 percent if you had none of the risk criteria, 46 percent if you have one of the critieria, and 72 percent if you have both criteria.