Myeloma Action Month: Understanding a Cancer of the Plasma Cells

What the month is

Every March, the International Myeloma Foundation runs Myeloma Action Month. Its 2026 campaign is built around the hashtag #MoreThanMyeloma, and it includes a global "Light the World Red" effort.

The foundation's own framing is worth noting. It says myeloma is the second most common blood cancer, and that awareness of it remains low. This page is an attempt to fix a small part of that.

What plasma cells do, and what goes wrong

Plasma cells are white blood cells. They develop from B lymphocytes in the bone marrow, and their job is to make antibodies that fight infection.

In myeloma, one plasma cell clone multiplies out of control. The abnormal cells build up in the marrow and form tumors in many bones. They also churn out a single useless antibody, called M protein or monoclonal protein.

Three problems follow from that.

The marrow gets crowded, so fewer red cells, white cells, and platelets are made. The bones are damaged and weakened. And the M protein and released calcium strain the kidneys.

A family of related conditions

Myeloma sits at one end of a spectrum. NCI's clinical summary groups it with three relatives, all defined by an M protein.

MGUS stands for monoclonal gammopathy of undetermined significance. There is an M protein and under 10% plasma cells in the marrow, but no symptoms. It is not cancer.

Isolated plasmacytoma of bone is a single bone lesion, with under 10% plasma cells elsewhere.

Extramedullary plasmacytoma is a single soft-tissue lesion, most often in the nasopharynx, tonsils, or sinuses.

Multiple myeloma means multiple bone lesions and symptoms.

NCI notes that people with MGUS or smoldering myeloma do not need immediate treatment, but do need careful follow-up for signs of progression. Separating stable disease from disease that is moving is the central clinical problem here.

What counts as active disease

Treatment is not triggered by a number on a lab report alone. The International Myeloma Working Group criteria, reproduced in NCI's summary, define active myeloma needing therapy by findings including:

• Calcium more than 1 mg/dL above the reference range.
• Creatinine above 2 mg/dL, or creatinine clearance under 40 mL/min.
• Hemoglobin below 10.0 g/dL.
• One or more bone lesions on x-ray, MRI, or PET-CT.
• Plasma cells making up 60% or more of the marrow.
• A ratio of involved to uninvolved serum free light chains of 100 or more.
• More than one focal lesion of at least 5 mm on imaging.

Those thresholds are why myeloma is sometimes caught on a routine blood test long before anyone feels ill.

When to get checked

NCI says to check with a doctor about bone pain, especially in the back or ribs; bones that break easily; fever for no known reason or frequent infections; easy bruising or bleeding; trouble breathing; weakness of the arms or legs; and feeling very tired.

Two patterns deserve extra attention.

The first is back pain in an older adult that does not settle, particularly with a fracture from a minor fall. Myeloma weakens bone, and a break that seems out of proportion to the injury is worth investigating.

The second is high blood calcium. NCI lists its symptoms as loss of appetite, nausea or vomiting, thirst, frequent urination, constipation, deep tiredness, muscle weakness, and restlessness. That combination in someone with bone pain is a reason to seek care promptly rather than at the next routine visit. Our page on multiple myeloma symptoms goes through the picture in more detail.

There is no screening test for myeloma in the general population, and NCI does not publish evidence-based screening or prevention guidance for it. Symptoms and incidental lab findings are how it is found.

What treatment involves

NCI describes treatment in phases.

Induction is first, and its aim is to cut the amount of disease. For younger, fit patients who could have a transplant, that typically combines chemotherapy, a proteasome inhibitor such as bortezomib, a monoclonal antibody such as daratumumab, an immunomodulator such as lenalidomide, and the steroid dexamethasone.

A proteasome is the cell's protein disposal unit. Blocking it makes unwanted proteins pile up until the cancer cell dies. Myeloma cells, which manufacture enormous quantities of antibody, are unusually vulnerable to that.

Consolidation follows. High-dose chemotherapy is given, then the patient's own stored blood-forming stem cells are returned in an autologous transplant. Our guide to stem cell transplant explains what that involves.

Supportive care runs alongside all of it. Denosumab, a monoclonal antibody, is used to slow bone loss and reduce bone pain.

For disease that comes back, NCI notes that CAR T-cell therapy is used, and that venetoclax, a BCL2 inhibitor, is under study.

What the survival figures show

About 36,000 new myeloma diagnoses and 10,850 deaths are expected in the United States in 2026 — American Cancer Society projections, carried on SEER's myeloma page. The median age at diagnosis, 69, is a SEER measurement from cases diagnosed 2016 to 2022.

Staging behaves differently here. SEER classifies 96% of myeloma as distant at diagnosis, because plasma cell disease is in the marrow throughout the body from the start. That is not the same as a solid tumor that has spread.

Five-year relative survival across all stages was 63.7% for people diagnosed from 2016 through 2022. In 1975 it was around 25%.

That change came from the drug classes above. It is still a group figure covering every age and risk group, and it forecasts nothing for one person. Our overview of multiple myeloma covers staging and risk groups.

What to keep in perspective

An M protein on a blood test is not a myeloma diagnosis. Most people found to have MGUS never develop cancer, which is exactly why NCI treats it as something to monitor rather than treat.

Awareness also does not shorten the path to diagnosis on its own. What can shorten it is naming a symptom precisely — persistent bone pain, an unexplained fracture, repeated infections — instead of filing it under getting older.

Sources

• International Myeloma Foundation: Myeloma Action Month
• NCI PDQ: Plasma Cell Neoplasms Treatment (Health Professional Version)
• NCI PDQ: Plasma Cell Neoplasms Treatment (Patient Version)
• NCI SEER Cancer Stat Facts: Myeloma

How this article was prepared

An AI-assisted editorial system helped prepare this page. No named medical reviewer has reviewed it unless one is listed.

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