Multiple myeloma begins in a type of white blood cells, called plasma cells, that develop in your bone marrow. Metastatic multiple myeloma is when the cancer spreads to multiple parts of your body.

The American Cancer Society estimates that about 35,730 people will be diagnosed with multiple myeloma in 2023. “Multiple myeloma” is often shortened to “myeloma.”

Myeloma can cause tumors that develop inside your bones. These tumors can weaken your bones and create abnormal cells that crowd out healthy blood cells. According to the Canadian Cancer Society, most people with myeloma have multiple tumors by the time they’re diagnosed.

Myeloma cells can also spread outside your bone marrow and cause tumors in other parts of your body such as your respiratory tract or skin.

Myeloma currently isn’t curable, but it’s controllable with medications. Some people can live many years with their myeloma under control.

This article takes a closer look at metastatic myeloma, including common sites of metastasis and how it’s treated.

Multiple myeloma is a cancer that starts in white blood cells called plasma cells. These cells create antibodies that help your body fight infections.

Myeloma most commonly develops inside of your:

  • spine
  • ribs
  • breastbone
  • hips
  • shoulder blades
  • skull
  • upper arms or legs

Like with other cancers, myeloma cells have the potential to travel to other parts of your body. If myeloma spreads to other bones or areas, it’s sometimes referred to as metastatic multiple myeloma. In about 95% of people, the cancer is metastatic when it’s diagnosed.

When myeloma forms a tumor outside of your bone marrow, it’s called extramedullary disease. About half of people with extramedullary disease develop it within 19–23 months of their myeloma diagnosis.

About 0.5–4.8% of people have extramedullary disease when they receive a diagnosis of myeloma.

Most people have multiple tumors when they’re diagnosed. Myeloma is most likely to spread to other bones. The most common places multiple myeloma spreads to outside bone are your:

  • skin or muscle
  • lungs
  • lymph nodes
  • liver

Multiple myeloma spreads to the central nervous system in well under 1% of people. There have only been seven cases of people with spread to the spinal cord reported in scientific literature as of March 2023.

How common is multiple myeloma and who gets it?

Multiple myeloma is a relatively rare cancer. About 1 in 132 people in the United States develop multiple myeloma at some point in their life. Risk factors for myeloma include:

Was this helpful?

Myeloma is treated primarily with a combination of medications to reduce symptoms of the disease. These medications usually include:

Younger adults and people with better overall health are more likely to receive intensive treatment. Intensive treatment involves taking a high dose of chemotherapy and replacing damaged cells with a stem cell transplant.

CAR T-cell treatment is a type of immunotherapy available for some people who weren’t helped by other treatments. This treatment helps your immune system destroy cancerous cells but can cause serious side effects, such as a high fever or trouble breathing.

Is metastatic multiple myeloma curable?

Multiple myeloma isn’t considered curable. Treatment aims to reduce symptoms of the disease and to destroy cancer cells. Some people can live for many years with multiple myeloma.

Was this helpful?

The 5-year relative survival rate for multiple myeloma in the United States was 58% between 2012 and 2018. The 5-year relative survival rate is a measure of how many people with the cancer are alive 5 years later compared to people without the cancer.

For people with metastatic myeloma, the 5-year relative survival rate is about 57%. People with myeloma contained to a solitary tumor had a 5-year relative survival rate of around 79%. Only about 5% of people with myeloma have just one tumor.

Factors linked to poorer survival rates include:

  • developing disease outside of your bone marrow
  • having certain genetic abnormalities such as missing chromosome 13
  • having disease in your central nervous system
  • older age
  • higher levels of lactate dehydrogenase
  • higher levels of creatinine
  • lower levels of albumin
  • high levels of beta-2-microglobulin

Multiple myeloma starts in your bone marrow but can spread to many other body parts.

Metastatic myeloma is when your cancer has spread to multiple body parts such as other bones, skin, or muscles. Cancer that has spread outside of your bone marrow is associated with having a poorer outlook.

Doctors usually treat multiple myeloma with a combination of medications to decrease disease activity and reduce symptoms. Usually, these medications include chemotherapy, a steroid, and one of several targeted therapy drugs.