If you've been told you have non-secretory multiple myeloma, you may have questions about what the diagnosis means and how your healthcare team will follow the disease. Non-secretory multiple myeloma is a rare type of cancer of the plasma cells in the bone marrow called multiple myeloma.
What non-secretory multiple myeloma means
Most people with multiple myeloma have a monoclonal protein, called M protein, made by myeloma cells that can be found in the blood or urine. Doctors measure M protein to help diagnose multiple myeloma and see how it responds to treatment.
With true non-secretory multiple myeloma, standard blood and urine tests don't find M protein. A blood test for free light chains also does not show measurable changes linked to myeloma. True non-secretory multiple myeloma makes up about 1% to 3% of multiple myeloma cases. You also may hear it called non-secretory myeloma, non secretory myeloma or NSMM.
The name can be confusing. Non-secretory does not always mean that the myeloma cells make no antibody protein. In many people, the cells make the protein but do not release it into the blood and urine. In other people, the cells make little or no antibody protein, called immunoglobulin.
How non-secretory myeloma differs from light chain myeloma
Non-secretory myeloma and light chain myeloma are not the same. In light chain myeloma, the myeloma cells make only part of an antibody, called a light chain. Doctors can measure free light chains with a blood test.
Symptoms
Non-secretory myeloma can cause the same kinds of symptoms and health effects as other forms of multiple myeloma because the cancer still affects the bone marrow, bones and other organs.
Symptoms may include:
- Bone pain.
- Bones that break more easily.
- Tiredness or weakness from anemia.
- Frequent infections.
- Issues caused by high calcium levels in the blood.
These symptoms can have many causes. Because there may be no M protein to provide an early clue, finding non-secretory myeloma can require more reliance on bone marrow testing and imaging.
Diagnosis
Not finding M protein does not rule out multiple myeloma. Typically, a diagnosis of multiple myeloma requires at least 10% clonal plasma cells in the bone marrow or a plasmacytoma confirmed by biopsy. A plasmacytoma is a tumor made of plasma cells.
There also must be at least one myeloma-defining event. This can include anemia, high calcium or bone damage caused by myeloma. Certain bone marrow or imaging findings also can be myeloma-defining events.
Blood and urine tests are important. Tests for M protein and free light chains help doctors find out whether the myeloma is truly non-secretory or whether it is making a small amount of protein that can be measured.
A bone marrow aspiration and biopsy allows doctors to look directly at plasma cells. With bone marrow testing, health professionals also can look for chromosome and gene changes that provide information about the myeloma.
A laboratory test called flow cytometry can identify myeloma plasma cells and tell them apart from other plasma cells. After treatment, highly sensitive flow cytometry can look for very small numbers of myeloma cells that remain in the bone marrow.
Imaging is especially important. A PET-CT scan, low-dose whole-body CT or MRI can show bone damage and other areas affected by myeloma. These scans do not depend on finding M protein, so they can provide useful information about non-secretory myeloma. A PET-CT scan also is known as a positron emission tomography-computerized tomography scan.
Sometimes, other blood cancers or plasma cell cancers can look similar to myeloma. Doctors may use bone marrow findings, flow cytometry, genetic testing, imaging and other clinical information together to make the diagnosis.
Staging and risk
Doctors use the same approaches to stage non-secretory myeloma and assess its risk as they use for multiple myeloma overall.
Blood tests and tests of myeloma cells can show how much myeloma is present and give information about its risk. For example, changes in certain chromosomes or genes can identify myeloma that has a high risk of getting worse or coming back after treatment.
Even when M protein cannot be measured, doctors can use these findings to determine the myeloma stage and see whether it has high risk features.
Treatment
Treatment for non-secretory multiple myeloma typically follows the same overall approaches used for multiple myeloma. The main difference is that the care team cannot rely on M protein to measure the response.
Multiple myeloma treatment often includes a combination of medicines that attack myeloma cells in different ways. Some people also may have an autologous stem cell transplant, followed by maintenance treatment to help keep the myeloma under control. The treatment plan depends on factors such as overall health, the features and risk level of the myeloma, and whether a stem cell transplant is right for you.
You and your care team can make treatment decisions together. It helps to understand your type of myeloma, risk status, treatment options and how the disease will be monitored. Knowing more about multiple myeloma diagnosis and treatment can help you and your care team make decisions that are right for you.
Monitoring
Monitoring is one of the main ways non-secretory myeloma differs from most other types of multiple myeloma.
When a person has measurable M protein, changes in that protein can help show whether treatment is working or the cancer is returning. With true non-secretory myeloma, there is no M protein to follow.
Because of this, doctors depend more on imaging and bone marrow testing. PET-CT scans or other scans can be compared over time to see how well treatment is working. Bone marrow tests can show how much myeloma remains in the marrow. Flow cytometry can look for very small amounts of myeloma after treatment.
Other blood tests are still used to check blood cell counts, calcium, kidney function and other measures of health.
Early in treatment, ask your care team which tests will likely tell whether your treatment is working.
Outlook
Survival and life expectancy vary from person to person with non-secretory multiple myeloma.
Your outlook depends on many factors. These include the amount of myeloma in your body, chromosome and gene changes in the myeloma cells, your overall health, and how well the cancer responds to treatment.
Your care team can consider these factors together to give you a better idea of what to expect than a general survival statistic can.
Relapse
Multiple myeloma can become non-secretory multiple myeloma later.
Some people have a measurable M protein when multiple myeloma is first diagnosed. If the myeloma returns later, there may be no measurable M protein.
AL amyloidosis
Multiple myeloma can occur along with AL amyloidosis. AL amyloidosis happens when light chain proteins misfold and build up in tissues and organs. There is not enough evidence to say how often AL amyloidosis occurs specifically in people with true non-secretory multiple myeloma. If symptoms or test results raise concern about amyloidosis, your care team may recommend tests to check for it.
