“You have multiple myeloma” are the four most devastating and life-altering words I have ever heard, but what prompted this diagnosis?
Doctors have a set of agreed upon diagnostic criteria for every condition. This is what is used to confirm a diagnosis. However, it is important to know that diagnostic criteria are not set in stone. They can evolve and change when new evidence is learned. The same is true for new findings in smoldering myeloma to determine how likely patients will be to progress to active myeloma.
When I was diagnosed in 2008 the agreed upon criteria for active myeloma was having more than 10% plasma cells in the bone marrow or biopsy-proven bony or extramedullary plasmacytoma, and any one or more of the following CRAB features and myeloma-defining events:
In 2014, the International Myeloma Working Group updated the diagnostic criteria for active myeloma to include three new biomarkers entitled myeloma defining events. The three new criteria are:
So how important is this free light chain ratio over 100 when it comes to determining if smoldering myeloma will progress to active myeloma?
At the recent European Hematology Association (EHA) conference, Dr. Theresia Akhlaghi (@TAAkhlaghi for my fellow Twitter followers) from Memorial Sloan Kettering Cancer Center (MSKCC) presented a session entitled Evaluating Serum Free Light Chain Ratio as a Biomarker for Multiple Myeloma.
The free light chain ratio is a measurement that divides your involved light chain (kappa or lambda number) by your uninvolved light chain (kappa or lambda number). For example, if you had IgG kappa myeloma, you would divide your kappa number by your lambda number, giving you a ratio. A normal ratio between these two numbers is 0.26 - 1.65.
In her presentation she showed evidence that not everyone with a free light chain ratio greater than 100 was imminent to progress from smoldering myeloma to active myeloma. It should be noted that patients diagnosed with high risk smoldering myeloma were excluded from this research. In her presentation, Dr. Akhlaghi concluded that:
So the free light chain ratio is not alwasy an end-all, be-all measurement when it comes to smoldering myeloma progression.
Will there be an update to the active myeloma diagnostic criteria? This research will be discussed and validated before any changes are made by the IMWG, but this is important information to have if you are a smoldering myeloma patient deciding when treatment should be started.
about the author
Cynthia Chmielewski is a professional educator and myeloma advocate. As a former teacher, she now teaches myeloma patients how to advocate for themselves as the Director of HealthTree University.