Smoldering multiple myeloma (SMM) is an early precursor to a rare blood cancer known as multiple myeloma, which affects plasma cells. This type of cancer produces certain proteins that can be measured in both blood and urine. These proteins show up before a person has any symptoms of cancer.
Plasma cells are a type of white blood cell. They play an important role in the immune system. Plasma cells create antibodies, which are proteins designed to fight specific diseases.
Scientists discovered that plasma cells help direct the immune response to viral or bacterial infections. Plasma cells, in addition to secreting highly specific antibodies, can also act as a sensor to keep the immune response in check.
When they function correctly, plasma cells are vital to a healthy immune response. They identify invaders and rein in your body’s reaction to infection when you’re sick. Plasma cells are produced by B-cells in your bone marrow.
In multiple myeloma, plasma cells become cancerous and begin dividing rapidly. As a result, the malignant cells soon crowd out the healthy cells. These cancer cells can spread from marrow and invade the hard outer part of the bone. There, the cells clump to form tumors. When many tumors develop, this type of cancer is called multiple myeloma.
The cancer destroys the bones as it grows. High levels of calcium are circulated in the bloodstream as a result, which can subsequently lead to kidney damage.
Symptoms can include:
- bone pain in the back and ribs
- broken bones
- excessive thirst
- chronic fatigue
- weight loss
- frequent urination
- frequent infections
Anemia may develop as plasma cells increase and crowd red blood cells in the bloodstream.
Multiple myeloma, like other cancers, can be defined by stages. There are three stages of the disease, each more advanced than the one before. A precursor to phase stage 1 is known as SMM.
A person can have SMM for several years before they progress to stage 1 multiple myeloma. Even when there are no outward symptoms, the malignant plasma cells secrete proteins into your body. These proteins can be measured in the blood or urine of people who otherwise exhibit no signs of disease.
There may be lesions on the spines of people with SMM. One study showed that monitoring these tumors regularly with MRI can detect the progression of the disease.
People diagnosed with stage 1 have very few cancerous cells. They may be only slightly anemic and have normal levels of calcium in their blood. X-rays show only one area of bone damage.
By stage 2, more cancer cells are detected along with higher levels of calcium in the blood and worsening anemia.
The criteria to define stage 3 multiple myeloma includes:
- severe anemia
- large amounts of protein in the urine
- at least three areas of bone damage
- high levels of calcium in the bloodstream
Scientists don’t know what causes SMM or multiple myeloma. They believe age is a risk factor, as most people who develop it are over 65. African-Americans are twice as likely as Caucasians to be diagnosed, and more men are diagnosed than women.
Even at the smoldering stage, multiple myeloma can be detected with a blood test. If a person has SMM, the test will show that the cancer cells are producing a certain type of protein. Depending on test results, the doctor may order a bone marrow biopsy to check for malignant cells.
Other tests may be performed. They include:
- computed tomography (CT) scan
- magnetic resonance imaging (MRI)
People diagnosed with SMM may not need immediate treatment. The doctor will begin careful monitoring for any sign of progression. If it turns into stage 1 multiple myeloma, treatment usually includes chemotherapy and sometimes radiation.
In early stage multiple myeloma, a bone marrow transplant may help. The diseased marrow is removed before the patient is given high-dose chemotherapy. Afterward, healthy marrow is transplanted.
Much research is currently underway. Besides traditional treatment options, people who have been diagnosed with SMM may want to consider joining a clinical trial. By participating in a trial, you may benefit from new treatments well before they’re commercially available.