Treatments for specific types of multiple myeloma

Multiple myeloma involves the bone marrow and often affects multiple (more than 1) bones or many areas in a bone. As a result, it is usually widespread by the time it is diagnosed. Multiple myeloma treatment is based on whether or not a person has symptoms of the disease.

People with smouldering, or indolent, multiple myeloma usually don’t have treatment. You will go for regular tests every 3–6 months to look for signs that the disease is progressing to active multiple myeloma. This is called watchful waiting. You may have treatment for smouldering multiple myeloma:

• if you have a very high risk of developing multiple myeloma within 2 years of a diagnosis
• when the signs and symptoms of multiple myeloma appear or change
• if you are participating in a clinical trial

You have a very high risk of smouldering multiple myeloma developing into active multiple myeloma within 2 years of a diagnosis if you have the following:

• Plasma cells make up 60% or more of the blood cells in the bone marrow.
• The serum free light chain ratio is 100 or greater.
• An MRI shows more than one area of bone or bone marrow destruction (breakdown).

People with active multiple myeloma have symptoms related to the disease. Your healthcare team will first decide whether or not you can have a stem cell transplant. This will help them choose which treatments you will have. The following are treatment options for active multiple myeloma. The types of treatments given are based on the unique needs of the person with cancer.

There are 3 main treatment phases in active multiple myeloma.

Induction therapy is the first phase of treatment for multiple myeloma. The goal of induction therapy for multiple myeloma is to lower the number of plasma cells (myeloma cells) in the bone marrow and the M-proteins made by the myeloma cells. Induction therapy often includes targeted therapy and other drugs such as chemotherapy or corticosteroids or both.

Consolidation therapy for multiple myeloma is given after a stem cell transplant. It’s a short course of chemotherapy, sometimes given with targeted therapy and a corticosteroid, which can help improve the outcome of a stem cell transplant.

Maintenance therapy is given after other treatments to help multiple myeloma stay in remission. Maintenance therapy is used after a stem cell transplant or when chemotherapy is given alone. The drugs used in maintenance therapy are usually targeted therapy.

The following are treatments for active multiple myeloma.

Most people with multiple myeloma will be treated with targeted therapy. Targeted therapy may be used before a stem cell transplant or as part of treatment in people who can’t have a stem cell transplant.

Targeted therapy is often first given as induction therapy. It may also be used right after a stem cell transplant (called consolidation therapy) and after consolidation therapy to help multiple myeloma stay in remission (called maintenance therapy).

Chemotherapy is also a main treatment for multiple myeloma. Chemotherapy may be given before a stem cell transplant. Chemotherapy is first given as induction therapy and then again as high-dose chemotherapy (called conditioning) in preparation for a stem cell transplant. Chemotherapy may also be given right after a stem cell transplant (called consolidation therapy) and to help multiple myeloma stay in remission (called maintenance therapy). There are many types of chemotherapy drugs that are used to treat multiple myeloma.

A stem cell transplant may be offered for active multiple myeloma. Your doctor will tell you if you are able to have a stem cell transplant. If you can have a stem cell transplant, you will have high-dose chemotherapy first to destroy the cells in the bone marrow.

Radiation therapy may be used if other treatments, such as chemotherapy, aren’t working and bone tumours are causing pain. Radiation therapy may also be used to prevent a fracture (break) in a diseased bone and to treat fractures or spinal cord compression.

In rare cases, surgery may be used for multiple myeloma if there is spinal cord compression or to place metal rods or plates to support weakened bones and prevent or treat fractures.

Supportive therapy is used to prevent or control health problems and complications related to active multiple myeloma. Supportive therapy for multiple myeloma includes the following.

• Corticosteroids, such as dexamethasone (Decadron, Dexasone) and prednisone, help to lessen some chemotherapy side effects like nausea and vomiting.
• Bisphosphonates help slow down bone destruction caused by myeloma cells.
• Denosumab (Xgeva) helps reduce the risk of bone problems caused by multiple myeloma.
• Colony-stimulating factors (CSFs) help the body make new red blood cells and white blood cells.
• Antibiotics and other drugs help prevent infection.
• Plasmapheresis is a procedure that helps remove M-protein from the blood, which can cause blood to thicken (called hyperviscosity). An M-protein is a type of immunoglobulin that is produced in higher than normal amounts in a person with multiple myeloma.

A solitary plasmacytoma has some of the same characteristics of active multiple myeloma but instead of multiple tumours in the bone, there is only one tumour. The bone tumour is called a solitary plasmacytoma. The main types of treatment for a solitary plasmacytoma are:

• radiation therapy
• surgery to remove the tumour

Extramedullary plasmacytoma is a unique type of multiple myeloma that starts outside the bone marrow (extramedullary) in soft tissues of the body, such as the nasal cavity or larynx. It is treated differently from multiple myeloma that affects the bone. The main types of treatment for an extramedullary plasmacytoma are:

• radiation therapy
• surgery to remove the tumour

Relapsed disease means the cancer has come back (recurred) after it has been treated. Refractory disease means the cancer is resistant (does not respond) to the first or most recent treatment given.

You may be offered one or more of the following treatments for relapsed or refractory multiple myeloma:

• watchful waiting (for people whose disease is stable)
• targeted therapy
• chemotherapy
• stem cell transplant (including those who have already had a stem cell transplant)
• radiation therapy
• supportive therapy

Some clinical trials in Canada are open to people with multiple myeloma. Clinical trials look at new ways to prevent, find and treat cancer. Find out more about clinical trials.