Light chain myeloma is a less common type of multiple myeloma. About 20 percent of people with myeloma are diagnosed with this type. Although light chain myeloma is in many ways similar to other types of myeloma, it may come with a higher risk of kidney damage and, potentially, a worse prognosis (outlook).

Read on for more details about the symptoms, diagnosis, treatment, and life expectancy associated with light chain multiple myeloma.

What Are Light Chains in Multiple Myeloma?

Multiple myeloma begins in the bone marrow, where white blood cells are formed. When the body detects an infection, some white blood cells transform into plasma cells. It’s the job of plasma cells to produce proteins known as immunoglobulins, or antibodies, which work to eliminate dangerous bacteria and viruses. People diagnosed with multiple myeloma have abnormal plasma cells that don’t work properly. Instead, they produce dysfunctional immunoglobulins that harm the body. These abnormal immunoglobulins are called monoclonal proteins, or M proteins.

Normal immunoglobulins are shaped like a Y, with four pieces linked together — two longer “heavy” chains and two shorter “light” chains. M proteins are excess quantities of one of these types or combinations of chains. People with light chain myeloma produce only the light chain part of abnormal immunoglobulins, which is also known as Bence Jones proteins.

Light Chain Myeloma vs. Heavy Chain Myeloma

Most cases of multiple myeloma are heavy chain myeloma. In this type, the only abnormal immunoglobulin proteins present are the heavy chains — the proteins that form the stem of the Y. An even rarer type is nonsecretory myeloma, in which there are no abnormal proteins.

Symptoms of Light Chain Multiple Myeloma

For the most part, light chain multiple myeloma symptoms are similar to general symptoms of multiple myeloma.

Bone Damage

Because multiple myeloma affects the bone marrow, about 85 percent of people with multiple myeloma will experience bone damage, often in the spine, pelvis, or ribs, according to the Multiple Myeloma Research Foundation. Bone lesions often lead to bone pain or fractures.

Gastrointestinal and Urinary Problems

Hypercalcemia (excess calcium from bone damage) can cause increased urination and gastrointestinal problems like stomach upset, excessive thirst, and diarrhea.

Neurological Symptoms

Hypercalcemia can also cause changes in mental state, such as confusion and drowsiness.

Anemia

Myeloma’s effects on the bones can lead to anemia — a deficiency of hemoglobin or red blood cells — and lowered immunity because there are no longer enough normal white blood cells to fight infection. Anemia can cause fatigue and weakness.

Kidney Damage

One common effect of light chain multiple myeloma is kidney damage and kidney failure, when the kidneys stop working effectively. About 40 percent of people with myeloma also have kidney damage at the time they’re diagnosed with the blood cancer. People with light chain myeloma are much more likely to experience kidney failure than those with non-light chain myeloma.

Although hypercalcemia and heavy chain proteins can damage the kidneys, light chain proteins are also a major factor in kidney problems with myeloma. Because the light chains are so small, they easily circulate in the bloodstream. The kidneys contain tiny filters called glomeruli, which remove waste materials from blood and send them into urine. When excess light chains enter the glomeruli with the blood, they mix with other proteins and clog the filters, causing inflammation and injuring kidney tissue.

Over time, the buildup of light chains can cause permanent damage and kidney failure. Symptoms of kidney failure include urinary changes, fatigue, nausea, swollen feet and ankles, itching, shortness of breath, and high blood pressure.

Diagnosis of Light Chain Multiple Myeloma

Tests to detect light chain multiple myeloma are the same as those for detecting multiple myeloma generally. Your doctor might order:

• Blood tests to detect M proteins that can indicate the aggressiveness of multiple myeloma
• Urine and blood tests to check kidney function and find abnormal proteins
• Bone marrow biopsy to look for cancer cells
• Imaging tests such as X-rays, magnetic resonance imaging (MRI), positron emission tomography (PET), and computed tomography (CT) scans to see damage to the bones or other organs

For a specific diagnosis of light chain multiple myeloma, a blood test called serum-free light chain must show a particular level of excess light chains. Urine tests may also confirm the presence of light chains.

Treatment of Light Chain Multiple Myeloma

Some people without symptoms may not require treatment at the time of diagnosis. For those who do, most treatment options for light chain multiple myeloma are similar to those for other forms of myeloma. Treating light chain multiple myeloma can be complicated by the light chains’ tendency to cause kidney damage. As many as 15 percent of people require hemodialysis (removal of wastes and water from blood) to help their kidneys function at the time they’re diagnosed with myeloma, according to the Clinical Journal of the American Society of Nephrology.

Other treatments that may be recommended for light chain myeloma include:

• Bortezomib (Velcade)
• Lenalidomide (Revlimid)
• Carfilzomib (Kyprolis)
• Corticosteroids
• Plasmapheresis (plasma exchange) to remove light chains from the blood

Prognosis and Life Expectancy With Light Chain Myeloma

For people diagnosed with multiple myeloma between 2014 and 2020, the five-year survival rate (percentage of people still alive after five years) is 61.1 percent. This statistic applies to people with multiple myeloma in general. For people with light chain myeloma, survival may be shorter — perhaps by as much as two years. Doctors believe this is likely due to kidney damage caused by light chains.

Speak with your doctor about your risk factors and prognosis. If you have trouble sticking with your myeloma treatment regimen, be open with your oncology team about these issues. They can help you find ways to stay on track with your treatment plan. You can also ask your oncologist if there are any promising clinical trials you might be eligible to join.

Talk With Others Who Understand

MyMyelomaTeam is the social network for people with multiple myeloma and their loved ones. On MyMyelomaTeam, more than 25,000 members come together to ask questions, give advice, and share their stories with others who understand life with myeloma.

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