Multiple myeloma is a blood cancer that forms in plasma cells, a type of white blood cell. Healthy plasma cells make proteins called antibodies. Antibodies work with other parts of the immune system to help protect the body from germs.

In multiple myeloma, cancerous plasma cells build up in bone marrow. The bone marrow is the soft, spongy tissue inside most bones where blood cells are made.

Myeloma cells make proteins that are not typical. These proteins are called monoclonal proteins, also known as M proteins. These proteins can build up and damage organs, such as the kidneys.

Multiple myeloma is generally preceded by a condition called monoclonal gammopathy of undetermined significance (MGUS). In MGUS, the amount of monoclonal protein is low, and the plasma cell condition doesn't cause myeloma-related organ damage. Most people with MGUS don't develop multiple myeloma.

Multiple myeloma, leukemia and lymphoma are blood cancers, but they start in different tissues or cells. Multiple myeloma starts in plasma cells. Leukemia happens when white blood cells that are not usual grow in excess and don't work as they typically do in blood-forming tissues such as bone marrow. Lymphoma starts in immune cells called lymphocytes.

Treatment can help control multiple myeloma, reduce complications and ease symptoms. It may help people live longer.

Types

Active multiple myeloma

Active multiple myeloma is diagnosed when testing shows a plasma cell condition and at least one myeloma-defining event. These events include myeloma-related organ damage or certain test findings that show a high risk of organ damage. Active multiple myeloma generally needs treatment.

Smoldering multiple myeloma

In smoldering multiple myeloma, blood or bone marrow test results show a plasma cell condition, but there is no myeloma-defining event. The condition hasn't caused organ damage or bone lesions. Most people are monitored instead of being treated right away. People with high-risk smoldering multiple myeloma may be offered treatment.

Some people with multiple myeloma have no symptoms at first. Symptoms may include:

• Bone pain, especially in the back, chest or hips.
• Weak or easily broken bones.
• Tiredness.
• Frequent infections.
• Shortness of breath.

Multiple myeloma can cause a high level of calcium in the blood, called hypercalcemia. Symptoms of high calcium can include:

• Nausea.
• Constipation.
• Loss of appetite.
• Confusion or trouble thinking clearly.
• Weakness.
• Feeling very thirsty.
• Needing to urinate often.

When to see a doctor

Make an appointment with a doctor or other healthcare professional if you have any of these symptoms or other symptoms that worry you.

It's not clear what causes multiple myeloma.

The disease develops through several changes in plasma cells and in the bone marrow. These changes allow myeloma cells to survive and build up in the bone marrow.

Multiple myeloma involves genetic changes in cancer cells. Having a close family member with multiple myeloma or a related plasma cell condition also raises the risk of developing the disease. But the disease doesn't follow one simple inherited pattern.

Many factors can raise the risk of multiple myeloma.

• Age. The risk of multiple myeloma goes up with age. The median age at diagnosis is about 65.
• Sex at birth. Men are more likely to develop the disease than are women.
• Race. In the United States, Black people are more likely to develop multiple myeloma than white people.
• Family history of multiple myeloma. Having a sibling or parent with multiple myeloma raises the risk of having the disease.
• MGUS. Having MGUS raises the risk of multiple myeloma. But most people with MGUS do not get multiple myeloma.

Complications of multiple myeloma include:

• Infections. Multiple myeloma can make it harder for the immune system to fight bacterial and viral infections.
• Bone issues. Multiple myeloma can cause bone pain, thinning bones and broken bones.
• Kidney issues. Multiple myeloma may damage the kidneys and may lead to kidney failure.
• Anemia and other blood cell conditions. Myeloma cells interfere with blood cell production in the bone marrow. This can cause a low red blood cell count, called anemia.

Prevention

No lifestyle or environmental change is known to prevent multiple myeloma. Because no direct cause has been found, a diagnosis doesn't mean you did anything to cause it.

Sometimes a blood test for another condition shows a result outside the expected range. This may lead a healthcare professional to order tests for multiple myeloma. Your care team also may do a physical exam and review your medical and family history.

Your care team also looks for organ damage due to multiple myeloma. The team looks for four types of organ damage, known as CRAB: high blood calcium, kidney damage, anemia and bone lesions. These findings can help diagnose active multiple myeloma. Certain biomarkers can establish active multiple myeloma before classic CRAB organ damage develops.

Several tests and procedures may be used to diagnose multiple myeloma.

• Blood tests. The M proteins made by myeloma cells can show up in a sample of blood. Blood tests also may measure beta-2-microglobulin, which helps determine stage and estimate outlook.
  
  Other blood tests check blood cell counts and levels of calcium, hemoglobin, albumin, lactate dehydrogenase and immunoglobulin. The tests also show how well the kidneys work.
• Urine tests. Urine tests can find monoclonal proteins and monoclonal free light chains. Free light chains in urine also are called Bence Jones proteins.
• Bone marrow tests. Bone marrow biopsy and bone marrow aspiration collect bone marrow samples for testing. These tests show the percentage of plasma cells that are cancerous. Bone marrow has a solid and a liquid part. In a bone marrow biopsy, a needle is used to collect a small amount of the solid bone marrow tissue. During a bone marrow aspiration, a needle removes a sample of the fluid in the liquid marrow. The samples are typically taken from the hip bone.
  
  The samples go to a lab for testing. In the lab, tests look for myeloma cells. If they are found, the tests provide other information about them. For example, a test called fluorescence in situ hybridization (FISH) looks for chromosome changes in plasma cells.
• Imaging tests. Imaging tests look for bone issues linked with multiple myeloma. Imaging tests may include whole-body low-dose CT, positron emission tomography (PET)-CT or MRI. X-rays also sometimes may be used, but they are less sensitive for finding myeloma-related bone damage.

Active multiple myeloma generally needs treatment. If you have smoldering multiple myeloma, your care team may suggest regular monitoring with blood, urine and imaging tests. Your care team may offer you treatment if you have high-risk smoldering myeloma.

Treatment goals and timing

Treatment can control myeloma, lower the risk of complications and ease symptoms. You may not need treatment right away if you have smoldering multiple myeloma.

Monitoring may include regular checkups and blood and urine tests. Sometimes you may have imaging or bone marrow tests too.

You and your healthcare team may decide to start treatment if your multiple myeloma is getting worse, also called progressing, or has become active. This decision is based on the results of regular tests, symptoms and other factors.

How treatment is planned

Your treatment plan depends on whether you are eligible for an autologous stem cell transplant. Your care team considers several factors when deciding this. These factors include your age and overall health, frailty, other conditions, kidney function, and treatment goals. Eligibility is not based only on your age or kidney function.

Your treatment plan also may need to change based on factors such as how well the treatment works, any side effects you have, how well your organs are working and your treatment goals. Side effects of treatment vary depending on the medicines and procedures your care team uses.

In multiple myeloma treatment, your first treatment often combines several medicines to help attack myeloma in different ways. For many people who are eligible for transplant, these include daratumumab or isatuximab along with bortezomib, lenalidomide and dexamethasone. Other combinations may be used based on overall health, frailty, kidney function and whether other treatment is planned. Early treatment can include targeted therapy, immunotherapy, corticosteroids and, sometimes, chemotherapy.

Medications

Your care team may give you medicines to treat myeloma in different ways. Some act directly on myeloma cells. Others help the immune system attack the cells or help other treatments work.

• Targeted therapy. Targeted therapy uses medicines that act on specific proteins or processes the cancer cells need to survive. By blocking the proteins or processes, targeted treatments can cause cancer cells to die. Therapies include monoclonal antibodies and proteasome inhibitors.
• Corticosteroids. Corticosteroid medicines such as dexamethasone work directly against myeloma. These medicines are part of many multiple myeloma treatment combinations. They help control swelling and irritation, called inflammation, in the body. The care team may need to lower the dose after several months — or sooner if you have side effects.

Immunotherapy

Immunotherapy helps the body's immune system find and attack myeloma cells in different ways. Immunotherapies used for multiple myeloma include bispecific antibodies and chimeric antigen receptor (CAR)-T cell therapy. The immune system fights off diseases by attacking germs and other cells that shouldn't be in the body. Myeloma cells can interfere with the typical immune system process. Side effects of immunotherapy include infections and reactions to the medicines.

Bispecific antibodies attach to a myeloma cell and a T cell at the same time, helping the T cell attack the myeloma cell.

CAR-T cell therapy uses your own T cells, a type of white blood cell. This treatment begins with your care team collecting T cells from your blood and sending them to a lab. In the lab, the cells are changed so that they can recognize a marker on the surface of the myeloma cells.

Next, the changed cells are returned to your body through infusion. The CAR-T cells then multiply and can find and attack multiple myeloma cells.

CAR-T cell therapy can cause cytokine release syndrome. This can cause symptoms such as fever, tiredness, headache, low blood pressure and low blood oxygen levels. When serious, cytokine release syndrome can affect how well organs work.

Other CAR-T side effects can include nervous system issues, low blood cell counts, low levels of antibodies called immunoglobulins and serious infections.

Your care team monitors you carefully during and after these treatments. The team has a plan to prevent and treat side effects.

Chemotherapy

Chemotherapy is sometimes used to treat multiple myeloma. Chemotherapy uses strong medicines to kill cancer cells. High-dose chemotherapy, usually melphalan, is used before an autologous stem cell transplant.

Chemotherapy side effects depend on the medicine and dose used.

Stem cell transplant

In an autologous stem cell transplant, also called a bone marrow transplant, blood-forming stem cells are collected from your blood. After you get a high dose of chemotherapy, the collected stem cells are returned through infusion. They help the bone marrow begin making blood cells again.

This type of transplant is an established treatment option for eligible people who have recently been diagnosed with multiple myeloma. Some people may choose or need to delay transplant after discussing the benefits and risks with their care teams.

In a stem cell transplant, the stem cells settle in the bone marrow and start making new blood cells.

After a stem cell transplant, many people get ongoing treatment, called maintenance therapy, to help delay disease progression. Treatment depends on disease risk, previous treatments and side effects of treatment.

A stem cell transplant can have many side effects or complications. Short-term effects can include:

• Nausea and vomiting.
• Tiredness.
• Loss of appetite.
• Hair loss.

Long-term complications can include:

• Other cancers.
• Liver, kidney, heart or lung complications.
• Weak muscles or bones.
• Infertility.

After a stem cell transplant, you have regular follow-up appointments and may need to keep taking some medicines.

Radiation therapy

Radiation therapy uses high-energy beams to kill cancer cells. The energy can come from X-rays, protons or other sources. It may ease pain or treat a tumor called a plasmacytoma, spinal cord compression or a specific area of bone disease.

Relapsed multiple myeloma

Relapsed multiple myeloma is disease that returns or gets worse after it got better after treatment.

Treatment after relapse depends on which medicines you have received, whether the myeloma is resistant to them and how long the myeloma was controlled by previous treatment. Treatment also depends on how fast the myeloma is progressing and which parts of the body are affected. Your care team considers any ongoing side effects, disease risk, other medical conditions and your treatment goals when recommending treatment for relapsed multiple myeloma.

A previously effective medicine sometimes can be used again if the myeloma remained controlled for a period of time after treatment ended and if the myeloma isn't resistant to medicines.

Sometimes, an autologous stem cell transplant may be done to treat relapse if you haven't had a previous transplant. A repeat transplant generally is only done for people who have had a long remission, typically more than 4 or 5 years.

CAR-T cells, bispecific antibodies and other newer immunotherapies are important options in previously treated multiple myeloma.

Refractory multiple myeloma

Refractory multiple myeloma doesn't get better with treatment or gets worse during or soon after treatment.

For this condition, treatments may be similar to those for relapsed multiple myeloma. Treatment can include targeted therapy, immunotherapy, chemotherapy, corticosteroids and bispecific antibodies. The choice depends on the treatments already used and which medicines no longer work against the myeloma.

Treating complications

Treatment also may include managing complications of multiple myeloma. For example:

• Bone pain. Pain medicines, radiation therapy and surgery may help control bone pain.
• Kidney damage. Myeloma-related kidney damage needs prompt treatment. Severe kidney damage may require dialysis. Stable kidney issues don't always prevent a person from being able to get a stem cell transplant.
• Infections. Vaccines can help prevent infections, such as the flu and pneumonia.
• Bone loss. Bone-modifying medicines may help reduce bone loss and broken bones.
• Anemia. Treatment for anemia depends on its cause and severity. Treatment can include a blood transfusion or, sometimes, medicines that can help the body make red blood cells.

Newer treatment advances

Research on new treatments is ongoing. Treatment advances include CAR-T cell therapies and bispecific antibodies that redirect T cells toward markers on myeloma cells.

Treatment sequencing means using treatments in a planned order. A T-cell-redirecting treatment used earlier can affect the safety or effectiveness of a later one.

As you go through treatment for multiple myeloma, rest when you need to. Eat nutritious foods when you can. Ask your care team what activities are safe for you to do. Finding ways to manage stress and anxiety also can be helpful. Options may include:

• Meditation or mindfulness.
• Relaxation exercises.
• Physical activity.
• Yoga.
• Music therapy.
• Hypnosis.
• Tai chi or qigong.

Talking with a mental health professional also may help you manage stress, anxiety and depression.

Talk with your healthcare professional before trying a new approach. Ask whether it is safe for you during treatment.

A cancer diagnosis can be a shock. With time, you may find ways to cope with the stresses of living with cancer. These ideas may help:

• Learn about your condition. Learn about multiple myeloma so that you feel comfortable making decisions about your care. Ask your healthcare team about your treatment options and their side effects.

Ask your healthcare team to recommend reliable sources of information. You may start with the National Cancer Institute and the International Myeloma Foundation.

• Ask for support. This may help you cope with issues and worries that might happen. Ask friends, family and other people you trust for support.

A support group of people coping with cancer may be helpful. People you meet in support groups can offer advice for dealing with day-to-day issues. You can join some support groups online.

• Set goals you can meet. Having goals may help give you a sense of purpose. Choose small goals that fit your health and energy level.

If you have multiple myeloma, you may be referred to a specialist. You may see one or both of these specialists:

• A doctor who specializes in treating blood and bone marrow conditions, called a hematologist.
• A doctor who specializes in treating cancer, called an oncologist.

Here's some information to help you get ready for your appointment.

What you can do

A family member or friend who goes with you can help you remember the information you're given.

Make a list of:

• Your symptoms, when they began and whether they've changed over time.
• Other medical conditions you have, especially any plasma cell conditions, such as monoclonal gammopathy of undetermined significance (MGUS).
• All your medicines, vitamins and supplements, including doses.
• Questions to ask your healthcare professional.

Questions to ask at your first appointment might include:

• What may be causing my symptoms?
• Are there other possible causes?
• What tests do I need?
• What are the next steps for diagnosis and treatment?

Questions to ask if you see a specialist include:

• Do I have multiple myeloma?
• What stage is my myeloma?
• Does my myeloma have any high-risk features?
• What are the goals of treatment for me?
• What treatment do you recommend?
• I have other health conditions. How can I best manage them with multiple myeloma?
• What are the possible side effects of treatment?
• If the first treatment isn't successful, what will be the next option?
• Am I eligible to have a stem cell transplant?
• Do I need a medicine to protect my bones?
• What is the outlook for my condition?

Be sure to ask all the questions you have about your condition.

What to expect from your doctor

Be prepared to answer some questions about your symptoms and your health, including:

• Do you have bone pain? Where?
• Are you nauseated or more tired or weaker than usual, or have you lost weight?
• Have you had repeated infections, such as pneumonia, sinusitis, bladder or kidney infections, skin infections, or shingles?
• Have you noticed changes in your bowel habits?
• Do you have a family history of plasma disorders such as MGUS?
• Do you have a history of blood clots?

Multiple myeloma staging systems use blood test results and, in some systems, genetic findings from the myeloma cells to estimate prognosis, also known as outlook. A higher stage generally means a less favorable outlook. But stage does not directly show how quickly myeloma is growing.

Staging terms

The International Staging System (ISS) and the Revised International Staging System (R-ISS) use stages 1 through 3. The Second Revision of the International Staging System (R2-ISS) uses stages 1 through 4.

Staging tests

ISS staging uses the levels of blood proteins beta-2-microglobulin and albumin. These levels help the care team place multiple myeloma into groups with different outlooks. In general, a higher beta-2-microglobulin level and a lower albumin level are associated with a less favorable outlook.

R-ISS also uses the level of lactate dehydrogenase (LDH) and certain chromosome changes in the myeloma cells. A test called fluorescence in situ hybridization (FISH) can find genetic changes.

Stage 1

In R-ISS, stage 1 means the beta-2-microglobulin level is below 3.5 milligrams per liter (mg/L) and the albumin level is at or above 3.5 grams per deciliter (g/dL). The LDH level is within the expected range. The myeloma cells don't have high-risk chromosome changes.

Stage 2

Stage 2 is when test results don't meet all the criteria for stage 1 or stage 3.

Stage 3

Stage 3 means the beta-2-microglobulin level is at or above 5.5 mg/L. The LDH level is also above the expected range, or the myeloma cells have high-risk chromosome changes.

Stage 4

R-ISS doesn't have a stage 4. In R2-ISS, there are four stages, and stage 4 is the highest risk group.

Multiple myeloma also can be given a risk level. Your care team evaluates risk features, such as certain chromosome or genetic changes in the myeloma cells. Stage and risk level are related but give different information to help estimate the prognosis of your condition.

Your healthcare team uses the multiple myeloma stage and risk level to understand your prognosis and plan your treatment.

Symptoms don't follow one fixed pattern for each stage of multiple myeloma. Treatment isn't based on stage alone. Symptoms depend on which parts of the body are affected. Treatment decisions also consider chromosome changes, how well your kidneys work and your overall health. Treatment also depends on whether a stem cell transplant is an option.

Learn about multiple myeloma symptoms and treatment.

Survival rates for multiple myeloma estimate the percentage of people with the condition who are expected to live a certain number of years after diagnosis. Relative survival estimates the survival after excluding the risk of death from other causes. For those diagnosed with multiple myeloma in the U.S. from 2016 to 2022, the five-year relative survival rate was almost 64%. From 2015 to 2024 in the U.S., the death rate fell about 3% each year.

These statistics describe large groups of people. They can't predict an individual's survival.

What you can do

Your outlook depends on factors such as age, overall health, disease stage and chromosome changes. It also depends on kidney function and how well treatment works. It also depends on whether myeloma returns or stops getting better during treatment. Your care team can discuss these factors with you.

Remission and relapse

Multiple myeloma can be treated, but it is not considered curable. Most people with multiple myeloma eventually have a relapse or develop myeloma that stops getting better with treatment. The length of remission often gets shorter after each relapse.

Treatment can lead to a partial or complete response. A complete response means that certain blood, urine and bone marrow criteria have been met. It doesn't mean that the myeloma is cured.