Overview

Multiple myeloma is a cancer that forms in a type of white blood cell called a plasma cell. Healthy plasma cells help fight infections by making proteins called antibodies. Antibodies find and attack germs.

In multiple myeloma, cancerous plasma cells build up in bone marrow. The bone marrow is the soft matter inside bones where blood cells are made. In the bone marrow, the cancer cells crowd out healthy blood cells. Rather than make helpful antibodies, the cancer cells make proteins that don't work right. This leads to complications of multiple myeloma.

Multiple myeloma treatment isn't always needed right away. If the multiple myeloma is slow growing and isn't causing symptoms, close watching might be the first step. For people with multiple myeloma who need treatment, there are a number of ways to help control the disease.

Symptoms

Early in multiple myeloma, there might be no symptoms. When signs and symptoms happen, they can include:

  • Bone pain, especially in the spine, chest or hips.
  • Nausea.
  • Constipation.
  • Loss of appetite.
  • Mental fogginess or confusion.
  • Tiredness.
  • Infections.
  • Weight loss.
  • Weakness.
  • Thirst.
  • Needing to urinate often.

When to see a doctor

Make an appointment with a doctor or other health care professional if you have symptoms that worry you.

Causes

It's not clear what causes myeloma.

Multiple myeloma begins with one plasma cell in the bone marrow. The bone marrow is the soft matter inside bones where blood cells are made. Something happens that turns the plasma cell into a cancerous myeloma cell. The myeloma cell begins making a lot more myeloma cells quickly.

Healthy cells grow at a set pace and die at a set time. Cancer cells don't follow these rules. They make a lot of extra cells. The cells continue living when healthy cells would die. In myeloma, the cancer cells build up in the bone marrow and crowd out the healthy blood cells. This leads to tiredness and not being able to fight infections.

The myeloma cells continue trying to make antibodies, as healthy plasma cells do. But the body can't use these antibodies, called monoclonal proteins or M proteins. Instead, the M proteins build up in the body and cause problems, such as damage to the kidneys. Myeloma cells can damage bones and increase the risk of broken bones.

A connection with MGUS

Multiple myeloma starts as a condition called monoclonal gammopathy of undetermined significance, also called MGUS. In MGUS, the level of M proteins in the blood is low. The M proteins don't cause damage in the body.

Risk factors

Factors that may increase the risk of multiple myeloma include:

  • Getting older. Most people are diagnosed in their late 60s.
  • Being male. Men are more likely to develop the disease than are women.
  • Being Black. Black people are more likely to develop multiple myeloma than are people of other races.
  • Having a family history of multiple myeloma. Having a sibling or parent with multiple myeloma increases the risk of the disease.
  • Having monoclonal gammopathy of undetermined significance, also called MGUS. Multiple myeloma starts as MGUS, so having this condition increases the risk.

There's no way to prevent multiple myeloma. If you get multiple myeloma, you didn't do anything to cause it.

Complications

Complications of multiple myeloma include:

  • Infections. Having multiple myeloma lowers the body's ability to fight infections.
  • Bone problems. Multiple myeloma can cause bone pain, thinning bones and broken bones.
  • Kidney problems. Multiple myeloma may cause problems with the kidneys. It can lead to kidney failure.
  • Low red blood cell count, called anemia. As myeloma cells crowd out healthy blood cells, multiple myeloma can also cause anemia and other blood problems.