Waldenstrom Macroglobulinemia

Waldenstrom macroglobulinemia (WM) is a rare, slow-growing cancer of certain white blood cells called B lymphocytes, primarily found in the bone marrow. These abnormal cells produce excessive amounts of a specific protein, immunoglobulin M (IgM), which can thicken the blood and cause various symptoms and complications throughout the body.

What is Waldenstrom Macroglobulinemia?

Waldenstrom macroglobulinemia (WM) is a rare type of cancer affecting specific white blood cells called B lymphocytes, which are part of your immune system. It primarily develops in the bone marrow, where these abnormal cells produce large amounts of an antibody protein called immunoglobulin M (IgM). This excess protein can thicken the blood and lead to various health problems.

Waldenstrom macroglobulinemia is considered a type of non-Hodgkin lymphoma, a cancer that starts in lymphocytes. In WM, the affected B lymphocytes, also known as lymphoplasmacytic cells, do not mature correctly. Instead, they accumulate in the bone marrow and other organs, such as the spleen and lymph nodes. A key feature of WM is the overproduction of a specific type of antibody called immunoglobulin M (IgM). Antibodies are proteins that normally help your body fight infections. However, in WM, the IgM produced is abnormal and does not function properly. This excess IgM is often referred to as a "monoclonal paraprotein" because it comes from a single type of abnormal cell. The large amount of IgM protein in the blood can make it thicker than normal, a condition known as hyperviscosity syndrome. This thickened blood can slow down circulation and affect how organs function. The abnormal cells can also interfere with the production of healthy blood cells in the bone marrow, leading to other complications.

Symptoms

Many people with Waldenstrom macroglobulinemia experience no symptoms, especially in the early stages, and the condition may be found during routine blood tests. When symptoms do occur, they are often vague and can include fatigue, weakness, easy bruising or bleeding, weight loss, and nerve issues like numbness or tingling.

Symptoms of Waldenstrom macroglobulinemia often develop slowly and can vary widely among individuals. The most common symptoms are general and non-specific, such as persistent tiredness (fatigue), a feeling of weakness, unexplained weight loss, fevers, and night sweats. These symptoms can be due to the cancer cells affecting normal body functions or causing anemia (low red blood cell count). Other symptoms arise from the excess IgM protein in the blood. This can lead to hyperviscosity syndrome, where thickened blood causes headaches, dizziness, confusion, and vision changes. The abnormal IgM can also interfere with blood clotting, resulting in easy bruising, nosebleeds, or bleeding gums. In some cases, the abnormal cells can accumulate in organs, causing an enlarged spleen or liver, or swollen lymph nodes. Nerve damage (neuropathy) can also occur, leading to numbness, tingling, or weakness, particularly in the hands and feet. It is important to note that these symptoms can also be caused by many other conditions, so a medical evaluation is necessary for proper diagnosis.

Causes & risk factors

The exact cause of Waldenstrom macroglobulinemia is not fully understood, but it involves genetic changes within B lymphocytes that lead them to become cancerous. While it's not inherited, certain factors can increase your risk, including older age, being male, having a family history of WM or other lymphomas, and certain autoimmune conditions.

Waldenstrom macroglobulinemia begins when a B lymphocyte develops a genetic mutation, or change, that causes it to grow and divide uncontrollably. These abnormal cells then produce excessive amounts of IgM protein. A common genetic mutation found in about 90% of people with WM is in a gene called MYD88. However, it's not clear what causes these initial genetic changes to occur. Several factors are known to increase a person's risk of developing WM. Age is a significant risk factor, as the condition is most often diagnosed in older adults, with the average age at diagnosis being around 70 years. Men are also more likely to develop WM than women. Other risk factors include ethnicity, with people of white descent having a higher risk. A family history of Waldenstrom macroglobulinemia or other types of non-Hodgkin lymphoma can also increase risk. Additionally, certain autoimmune conditions, such as Sjögren's syndrome, and infections like hepatitis C, have been linked to a slightly increased risk of developing WM.

How it's diagnosed

Diagnosing Waldenstrom macroglobulinemia typically involves a combination of physical exams, blood tests to check for abnormal proteins and blood cell counts, and a bone marrow biopsy. Imaging tests may also be used to assess the extent of the disease. These tests help confirm the presence of abnormal B cells and excess IgM protein.

If Waldenstrom macroglobulinemia is suspected, your doctor will usually start with a physical examination to check for signs like swollen lymph nodes or an enlarged spleen. Blood tests are crucial for diagnosis. These include a complete blood count (CBC) to check for anemia or low platelet counts, and tests like serum protein electrophoresis (SPEP) and immunofixation to detect and measure the amount of abnormal IgM protein in your blood. Your doctor will also measure the overall IgM level. A bone marrow biopsy is a key diagnostic procedure. During this test, a small sample of bone marrow is removed, usually from the hip bone, and examined under a microscope. This helps identify the presence of abnormal B cells (lymphoplasmacytic cells) and assess how much of the bone marrow is affected. Genetic tests, such as for the MYD88 mutation, may also be performed on the bone marrow sample. Additional tests might include urine tests to check for protein in the urine, and imaging scans like computed tomography (CT) or positron emission tomography (PET) scans. These imaging tests can help determine if the cancer has spread to other parts of the body, such as the lymph nodes or spleen, and are important for staging the disease and guiding treatment decisions.

Treatment options

Treatment for Waldenstrom macroglobulinemia depends on whether you have symptoms and the severity of the disease. For those without symptoms, doctors often recommend watchful waiting. When treatment is needed, options include chemotherapy, targeted therapies that block specific cancer pathways, immunotherapy to boost the immune system, and plasmapheresis to remove excess protein from the blood.

For people diagnosed with Waldenstrom macroglobulinemia who do not have symptoms, a "watchful waiting" approach is often recommended. This means your doctor will monitor your condition regularly without starting immediate treatment. Treatment typically begins only when symptoms develop or when the disease starts to cause complications. When treatment is necessary, chemotherapy drugs are commonly used to kill cancer cells. These can be given alone or in combination with other therapies. Targeted therapies, such as Bruton's tyrosine kinase (BTK) inhibitors, are a newer class of drugs that specifically block signals that cancer cells need to grow and survive. These can be very effective for many people with WM, especially those with the MYD88 mutation. Immunotherapy drugs, like rituximab, work by helping your immune system recognize and attack the cancer cells. These are often used in combination with chemotherapy. For people experiencing hyperviscosity syndrome due to very thick blood, a procedure called plasmapheresis may be performed. This involves removing blood, separating the plasma (which contains the excess IgM) from the blood cells, and returning the treated blood cells to the body, quickly reducing blood thickness.

Recovery & outlook

Waldenstrom macroglobulinemia is generally considered a chronic, incurable condition, but it is often slow-growing and highly treatable. Many people achieve periods of remission, where symptoms improve or disappear, and can live for many years with a good quality of life. The outlook varies greatly depending on individual factors, such as age, overall health, and response to treatment.

While there is currently no cure for Waldenstrom macroglobulinemia, advances in treatment have significantly improved the outlook for many people. It is often managed as a chronic disease, similar to other long-term conditions. Treatment aims to control the disease, manage symptoms, and prevent complications, allowing individuals to live well for extended periods. Many people with WM experience periods of remission, where the disease is inactive and symptoms are minimal or absent. However, the disease often recurs, requiring further treatment. The specific course of WM can vary widely, with some individuals having very slow-progressing disease for many years, while others may require more aggressive or frequent treatment. Factors influencing the outlook include a person's age, their overall health, the specific genetic mutations present in the cancer cells, and how well they respond to initial treatments. Regular follow-up appointments and ongoing monitoring are essential to manage the disease effectively and address any potential complications, such as infections or nerve damage, as they arise.

When to see a doctor

You should see a doctor if you experience persistent or worsening symptoms that could indicate Waldenstrom macroglobulinemia, such as unexplained fatigue, significant weight loss, easy bruising or bleeding, or new numbness or tingling. Seek immediate medical attention for severe symptoms like sudden vision changes, severe headaches, confusion, or significant weakness, as these could signal serious complications.

It is important to consult your doctor if you notice any new or concerning symptoms that persist. While many symptoms of Waldenstrom macroglobulinemia are vague, a medical evaluation can help determine their cause. Specifically, if you experience ongoing fatigue that doesn't improve with rest, unexplained weight loss, recurrent fevers or night sweats, or notice easy bruising or bleeding without injury, you should discuss these with your healthcare provider. Additionally, any new or worsening neurological symptoms, such as numbness, tingling, or weakness in your hands or feet, warrant a visit to the doctor. These could be signs of nerve damage related to WM. Certain symptoms require immediate medical attention as they could indicate a serious complication like hyperviscosity syndrome. These include sudden and severe headaches, confusion, dizziness, significant changes in your vision, or profound weakness. Do not delay seeking emergency care if you experience these severe symptoms. Early diagnosis and management of complications are crucial for your health.

Frequently asked questions

Is Waldenstrom macroglobulinemia a common cancer?

No, Waldenstrom macroglobulinemia is a rare type of cancer. It accounts for only about 1% to 2% of all blood cancers, making it much less common than other lymphomas or leukemias.

Can Waldenstrom macroglobulinemia be cured?

Currently, Waldenstrom macroglobulinemia is generally considered an incurable condition. However, it is often slow-growing and highly treatable, with many people achieving long periods of remission and living for many years with good quality of life.

What is the main problem caused by the excess IgM protein?

The main problem caused by the excess immunoglobulin M (IgM) protein is that it can thicken the blood, a condition called hyperviscosity syndrome. This can slow blood flow, leading to symptoms like headaches, dizziness, vision changes, and confusion.

Is Waldenstrom macroglobulinemia hereditary?

While a family history of Waldenstrom macroglobulinemia or other lymphomas can increase your risk, the condition itself is not directly inherited in a simple genetic pattern. It typically arises from acquired genetic mutations in B cells during a person's lifetime.

What is "watchful waiting" for WM?

Watchful waiting, also known as active surveillance, is an approach where doctors closely monitor people with Waldenstrom macroglobulinemia who do not have symptoms. Treatment is only started if symptoms develop or if the disease shows signs of progression.

How does plasmapheresis help with WM?

Plasmapheresis is a procedure used to quickly remove large amounts of the excess immunoglobulin M (IgM) protein from the blood. This helps to thin the blood, rapidly relieving symptoms caused by hyperviscosity syndrome, such as headaches, dizziness, or vision problems.

Sources

• MedlinePlus — Waldenstrom Macroglobulinemia
• Mayo Clinic — Waldenstrom Macroglobulinemia
• Cochrane Library — Waldenstrom Macroglobulinemia