Smoldering multiple myeloma (SMM) is when you have low levels of myeloma cells or m-protein. SMM is a precancerous condition that can turn into myeloma.

Smoldering multiple myeloma symptoms

People with smoldering multiple myeloma do not have signs of myeloma or organ damage.

To diagnose SMM, you will have blood or urine tests. These tests look for:

• A level of m-protein at 3.0 g/dL (3 grams in a deciliter of blood) or higher.
• A high level of plasma cells, at 10% to 60% of the blood cells in your bone marrow.

A range of 10% to 60% means out of every 100 blood cells, 10 to 60 are plasma cells. A normal level is about 2% to 3%. Out of every 100 blood cells, only 2 or 3 of them are plasma cells.

Risk of smoldering myeloma becoming multiple myeloma

Compared to monoclonal gammopathy of undetermined significance (MGUS), smoldering myeloma has a higher risk of turning into multiple myeloma. Only 1 or 2 out of every 100 people who have MGUS will develop multiple myeloma. 

But during their first 5 years with SMM, 10 out of every 100 people will get multiple myeloma. The risk falls after the first 5 years.

People with SMM can be at a low, intermediate (medium), or high risk for getting active multiple myeloma. MSK offers treatment that can delay SMM from getting worse.

Smoldering multiple myeloma treatment and monitoring

MSK will monitor SMM for signs it is turning into active multiple myeloma. Our doctors are very experienced in treating plasma cell disorders and multiple myeloma.

We’re also looking at ways to prevent SMM from becoming active myeloma.

Some people with smoldering myeloma are at high risk for getting active myeloma. MSK is researching whether treatment can delay symptoms, such as broken bones or kidney failure. We’re looking at whether we can stop the disease by changing your nutrition and microbiome.