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This page was updated on April 21, 2021.

About multiple myeloma

Multiple myeloma is a blood cancer also known as bone marrow cancer, because it develops in plasma cells in bone marrow. Plasma cells develop from B-cell lymphocytes, a type of white blood cell. Plasma cells help the body’s immune system fight disease by producing antibody proteins in response to bacterial infections or viruses.

When malignant plasma cells (cancerous cells called myeloma cells) collect in only one bone and form a single mass or tumor, it is called a solitary plasmacytoma. In most cases, however, the myeloma cells grow out of control and collect in many bones, often forming many tumors. When this happens, the disease is called multiple myeloma, also known as plasma cell myeloma.

Although it only accounts for about 1 percent of overall cancers, multiple myeloma is the third most prevalent blood cancer after non-Hodgkin lymphoma and leukemia. According to the American Cancer Society, about 34,920 new cases of multiple myeloma will be diagnosed in 2021—19,320 in men and 15,600 in women.

What causes multiple myeloma?

While cancer research has not determined the exact cause of multiple myeloma, several factors may increase the risk of plasma cell neoplasm diseases.

The risk factors for multiple myeloma include:

  • Obesity
  • Family history, with a sibling or parent who has had the disease increasing its likelihood as much as four times when compared to people without a family history of the disease
  • Personal history of monoclonal gammopathy of undetermined significance (MGUS), an abnormal line of antibody-producing plasma cells that begin to produce monoclonal antibody proteins (M proteins)
  • Radiation exposure

Learn about risk factors for multiple myeloma

Who gets multiple myeloma?

The incidence of multiple myeloma is twice as high in African Americans as in whites. Men are at a slightly increased risk of developing the disease compared to women.

Only a very small percentage of young adults are diagnosed with multiple myeloma, so young people are not considered a high-risk group. The majority of those diagnosed are over 65 years old. The average age at diagnosis is 69, according to the National Cancer Institute (NCI).

Multiple myeloma types

Multiple myeloma has many types, each based on the type of immunoglobulin (protein) produced by the abnormal plasma cells.

Although multiple myeloma affects the bones, it begins with abnormalities in the cells of the bone marrow. Therefore, multiple myeloma is different from bone cancer, in which cancer cells form in the hard, outer part of the bone.

Light chain amyloidosis is the term for a form of malignant plasma cell disorder that causes a smaller number of abnormal plasma cells in the bone marrow than multiple myeloma.

Smoldering multiple myeloma, also called asymptomatic myeloma, is a slow-growing form of the disease characterized by increased plasma cells in the bone marrow and the presence of monoclonal proteins, without the presence of symptoms.

Multiple myeloma is also divided into two categories:

  • Hyperdiploid multiple myeloma, where myeloma cells have more chromosomes than normal
  • Non-hyperdiploid multiple myeloma, including hypodiploid multiple myeloma, where myeloma cells have fewer chromosomes than normal

Learn more about types of multiple myeloma

Multiple myeloma symptoms

The early stages of multiple myeloma often display no symptoms. Symptoms typically don’t appear in multiple myeloma patients until the disease reaches an advanced stage. In some cases, the disease is discovered during a routine blood test or a test to diagnose another condition.

Multiple myeloma symptoms vary for each person. Common symptoms include:

  • Bone pain, often in the back or ribs
  • Unexplained bone fractures or lesions, usually in the spine
  • Fatigue, anemia (a shortage of red blood cells) and/or feeling of weakness
  • Recurrent infections and/or fevers
  • Shortness of breath
  • Weight loss
  • Nausea
  • Constipation
  • Increased thirst and urination

In addition to symptoms, multiple myeloma patients may develop one or more of the following conditions:

  • Low blood counts, including a low platelet count
  • Hypercalcemia (high calcium levels)
  • Kidney failure
  • Spinal cord compression

Learn more about the symptoms of multiple myeloma

Diagnosing multiple myeloma

Multiple myeloma is often difficult to diagnose, and may require several different tests to analyze. Tests for diagnosing multiple myeloma include:

Several different staging systems are used to rank the progress of multiple myeloma.

Learn about diagnostic procedures for multiple myeloma

Multiple myeloma treatments

Multiple myeloma treatment generally depends on the stage of the cancer, whether you are a candidate for a stem cell transplant, and other factors, such as personal preferences and needs. Treatment options for multiple myeloma may include:

  • Chemotherapy, including high-dose chemotherapy
  • Interventional radiology
  • Kyphoplasty
  • Radiation therapy
  • Stem cell transplantation
  • Targeted therapy, including the use of proteasome inhibitors such as carfilzomib or bortezomib, to prevent a toxic buildup of proteins inside a cell
  • Corticosteroids, such as prednisone and dexamethasone
  • Immunomodulatory drugs, such as lenalidomide, thalidomide or pomalidomide

Learn about treatment options for multiple myeloma