Understanding Smoldering Multiple Myeloma
Kristie L. Kahl: Can you explain what smoldering myeloma is?
Dr. Irene Ghobrial: Many patients come in to see us because they have back pain or anemia or kidney problems; however, if we know that every single patient who comes to see us with multiple myeloma likely had five years, 10 years of a precursor condition – meaning they were asymptomatic. They did not have any problems, but they also had the same cancer cells and the same protein in their blood. We don’t look for it because we don’t screen for multiple myeloma and that’s something we’re changing now with the PROMISE study.
When we identify those patients and they have more than 10 cancer cells in their bone marrow, we call this smoldering multiple myeloma and the name is exactly right. They’re almost going to myeloma, they’re almost on fire, and the question is what leads to that progression: How often do those patients go on to develop myeloma? Are they at high risk of developing it or not?
So when I see someone who’s doing great, who has no anemia, no lesions in their bones and doing well but they have a protein in their blood. They have myeloma cells in their bone marrow. Their first question is: Yes, I have this smoldering multiple myeloma but what’s my risk of progression to active disease and should I do something about it?
Kristie L. Kahl: Can you discuss what monoclonal gammopathy of undetermined significance, or MGUS, is?
Dr. Irene Ghobrial: MGUS is the one step before smoldering myeloma. If we look at the spectrum of the disease, people usually have MGUS first and then smoldering myeloma if they progress and then active myeloma. MGUS is basically the number of cells, if there is less than 10, although this is very arbitrary. MGUS risk is very small so that’s why we differentiate them because the chance of progression from MGUS to myeloma is only 1% per year .
Kristie L. Kahl: So what is the risk for smoldering myeloma to progress and how long can this happen after you receive a small during myeloma diagnosis?
Dr. Irene Ghobrial: We don’t know how many people have smoldering myeloma. If we think about the general population, we know that MGUS, or potentially smoldering myeloma, is actually very common – 5% of the population over the age of 50 are more common to have it; the African American population; or first-degree relatives of myeloma.
We start asking, well all of these people who are asymptomatic, how many of them would actually develop myeloma? How can we predict who will progress or not if I am today coming in to see a doctor and I have more than 10 plasma cells, I’m freaking out. I’m saying, okay I have myeloma right now, what are my chances of going in and having a fracture of my bones or having kidney damage.
The first thing to make sure is you don’t have active myeloma yet but you’re at risk. And the question is: What is that risk we look at clinical factors, what we call clinical markers, of progression – meaning the percentage of bone marrow cells, the light chain ratio, the protein in the blood, how high it is. And now we know that we also have genomic factors, meaning the type of cancer cells, are they aggressive? Do they like to grow very fast or are they just sitting around and growing very slowly? And they don’t have a problem of waiting years and years before they cause damage.