Myeloma and related plasma cell disorders

It is a condition in which one group of plasma cells grows out of control. Plasma cells are white blood cells in the bone marrow that make antibodies to fight infection. In these disorders, the abnormal cells make an antibody protein the body does not need, called M protein. NMDP notes that they are also called plasma cell dyscrasias. The World Health Organization’s 2022 classification groups them as plasma cell neoplasms and other diseases with paraproteins.

No. NCI says MGUS is not cancer but can become cancer. Multiple myeloma and plasmacytoma are cancers. NMDP says AL amyloidosis is not considered a cancer (malignancy), although it shares features with myeloma. POEMS syndrome is a rare condition linked to a group of abnormal plasma cells. Several of these disorders are treated with medicines also used for myeloma.

It can, but usually it does not. In most people with MGUS, the M protein level stays the same and causes no problems. NCI puts the yearly chance that MGUS turns into a blood cancer at 0.5% to 1% in population studies, and higher for people with risk factors. MGUS can also lead to amyloidosis, Waldenström macroglobulinemia (lymphoplasmacytic lymphoma) or chronic lymphocytic leukemia. NCI also notes that virtually all myeloma starts as MGUS. That is why people with MGUS have regular blood tests.

Usually not. NMDP says multiple myeloma is the most common reason for a stem cell transplant in the United States. Most people with myeloma who have one receive their own cells (an autologous transplant). In 2024, EBMT centers in Europe and nearby countries reported 13,694 own-cell transplants for myeloma and 89 donor transplants. A transplant with the person’s own cells is also used for some people with AL amyloidosis or POEMS syndrome. Since March 2021, CAR-T therapy has been approved in the U.S. for some adults whose myeloma came back or stopped responding after several other treatments. It is also made from the person’s own cells. A donor transplant is generally kept for selected people with high-risk myeloma. MGUS is usually just watched, and NCI says smoldering myeloma without symptoms can often be watched safely at first.

Mostly middle-aged and older adults. In U.S. cancer registry (SEER) data for 2019 to 2023, the median age at myeloma diagnosis was 69. NCI lists being Black, being male and having had MGUS or a plasmacytoma as risk factors for myeloma, along with exposure to radiation or certain chemicals. In the same data, non-Hispanic Black people were diagnosed with myeloma more than twice as often as non-Hispanic White people. This was true for both men and women. MedlinePlus Genetics explains that the gene changes in myeloma cells happen during a person’s life and are not inherited. Even so, close relatives of people with myeloma have a higher risk.

Not exactly. Plasma cells are a type of B cell, a white blood cell, so myeloma is a blood cancer. But it is its own group. When many myeloma cells are in the blood at diagnosis, it is called primary plasma cell leukemia. Since 2021, an expert group has set the line at 5% or more plasma cells on a blood smear, in someone with active myeloma. NCI lists Waldenström macroglobulinemia (lymphoplasmacytic lymphoma) among the plasma cell neoplasms, but it is a lymphoma, and NCI covers its treatment with non-Hodgkin lymphoma.

It depends on the disorder. NCI calls multiple myeloma highly treatable but rarely curable, and says median survival now exceeds 10 years. It says myeloma is potentially curable when it shows up as a single tumor (a plasmacytoma). MGUS usually needs no treatment at all, only regular check-ups. In a large Mayo Clinic study of POEMS syndrome, 62% of people were alive 10 years after diagnosis. Group figures cannot predict what will happen to one person.