This is the second part of our series about the condition based on our patient booklet “Fast Facts for Patients and their Supporters: Myeloma”, which is freely available online. This article addresses the types and effects of myeloma.

What Type of Myeloma Do I Have?

Myeloma can take a number of different forms, depending on the type of abnormal antibody (also known as immunoglobulin) produced by the myeloma cells. All antibodies have two light chains and two heavy chains: different types of antibody have different heavy chains (G, A, M, D or E) and light chains (kappa or lambda). Plasma cells in patients with myeloma secrete variable quantities of abnormal antibodies, called paraprotein, and/or free light chains.

Two-thirds of people with myeloma produce type G immunoglobulin (IgG) and they are said to have IgG myeloma. The next most common is IgA, while the rest (IgM, IgD and IgE) are very rare. About 1 in 5 people with myeloma produce abnormal levels of the light chain component of the antibody (also called Bence Jones protein). These people are said to have light chain myeloma (you may also see this referred to as Bence Jones myeloma).

The type of myeloma that you have will not affect the treatment you are offered, but it can make a difference to how the disease affects you. For example, light chain myeloma is most likely to cause kidney damage. In other types of myeloma, tumors called plasmacytomas are occasionally found inside or outside the bones.

Precursor conditions that develop into multiple myeloma: There are two other conditions that affect plasma cells: MGUS and smoldering myeloma. Both of these conditions can develop into myeloma – but not always!

• MGUS (monoclonal gammopathy of undetermined significance) is a precancerous condition in which a small number of myeloma cells (less than 10% of all plasma cells in the bone marrow) produce paraprotein. There are no other signs of myeloma. Only 1% of people with MGUS develop myeloma over the course of a year. Like myeloma, MGUS is most common in people over the age of 70.
• Smoldering myeloma is sometimes also called indolent or asymptomatic (symptomless) myeloma. 10–60% of plasma cells in the bone marrow are myeloma cells, which produce paraprotein. There are no other signs of myeloma.

Up to 20% of patients with smoldering myeloma can progress to myeloma in the first 5 years of diagnosis. You will not need treatment, but you will need to have regular blood tests to check that the disease is not progressing quickly.

The correct diagnosis must be made as soon as possible to find out which condition you have because active myeloma can be treated.

What Are the Effects of Myeloma?

The buildup of abnormal myeloma cells in the bone marrow, and the effect of this on the production of normal blood cells, result in a number of symptoms and complications.

The symptoms and signs of myeloma are often referred to by the abbreviation SLiM CRAB.

• Sixty percent (60%) plasmacytosis (an unusually large proportion of plasma cells in tissues, exudates or blood).
• Light chains – the serum free light chain ratio is greater than 100.
• MRI – one or more focal lesion on the MRI scan.
• Calcium levels increase in the blood (hypercalcemia), which can cause thirst, nausea, vomiting and confusion.
• Renal (kidney) damage or problems with blood clotting may arise as a result of abnormal proteins (paraproteins) produced by the myeloma cells. This can make you tired, itchy, breathless, sleepy or not able to think straight. Abnormal cell production also increases the risk of infections.
• Anemia (fewer red blood cells taking oxygen around the body) may make you look pale and feel tired or listless.
• Bone damage caused by myeloma cells in the bone marrow can lead to pain, fractures, a curved spine (spinal cord compression) and/or nerve problems.

The symptoms and complications of myeloma can affect multiple sites in the body.

The control of these symptoms and complications will be an essential part of your treatment.

Remember: the symptoms of myeloma may not be present all the time.

You may have long periods when the disease does not cause any symptoms (remissions), and periods when you do have symptoms that need to be treated (relapses). In other words, myeloma is a relapsing-remitting form of cancer.

Plan for your remissions and the things you’d like to do.

Please check out the other posts of our series here:

• What Is Myeloma, How Is It Diagnosed, Who Gets It, and Why?
• Myeloma: What Treatment Will I Receive?
• Stem Cell Transplantation for Myeloma

Information based on Fast Facts for Patients and their Supporters: Myeloma (Karger, 2017).