ITP and Blood Cancers: Is There a Link?

Both immune thrombocytopenia (ITP) and blood cancers can cause low platelet counts, but they do so in different ways. Although it’s uncommon, blood cancer can cause thrombocytopenia that may lead to symptoms like easy bruising and bleeding. While these can be concerning, treatments are available to manage them.

This article explores the relationship between ITP and blood cancers. You’ll learn how often ITP develops alongside blood cancer, how the conditions are diagnosed and treated, and how ITP may affect your prognosis (outlook) if you have blood cancer.

Can Blood Cancers Cause Secondary ITP?

ITP is classified as either primary or secondary. Primary ITP is diagnosed when there’s no known underlying cause. Secondary ITP occurs as a result of another health condition.

Your body makes new blood cells in the bone marrow, the spongy tissue inside your bones. Bone marrow produces:

• Red blood cells
• White blood cells
• Platelets

Some blood cancers can trigger secondary ITP by causing the immune system to attack and destroy platelets. However, blood cancers can also lower platelet counts by crowding out healthy bone marrow cells or as a side effect of cancer treatment. A low platelet count from these causes is not ITP.

It’s important to note that ITP isn’t a type of cancer. Instead, it can be a complication of certain blood cancers when the immune system destroys platelets. Most people living with ITP have the primary type, meaning the cause is unknown.

ITP is uncommon in people with blood cancer. It has been studied most extensively in chronic lymphocytic leukemia (CLL), in which estimates vary among studies. The risk also differs depending on the type of blood cancer.

Which Blood Cancers Are Associated With ITP?

Compared with other immune-related conditions, blood cancers are less likely to cause secondary ITP. Between 1 percent and 5 percent of people with the following blood cancers develop ITP:

• Chronic lymphocytic leukemia — Starts in the bone marrow and affects lymphocytes, a type of white blood cell that helps fight infections
• Small lymphocytic lymphoma (SLL) — Mainly affects the lymph nodes and other lymphatic tissues

SLL and CLL are different forms of the same disease. When there are more than 5,000 cancerous lymphocytes per microliter of blood, the condition is generally classified as CLL.

Studies also suggest that ITP can occur in people with other blood cancers. One hospital database report found that many people recorded as having both myeloid leukemia and ITP had acute myeloid leukemia (AML). However, studies like this can’t always show whether a low platelet count was caused by ITP, the leukemia itself, or cancer treatment.

AML is a fast-growing blood cancer that begins in the bone marrow. It affects myeloid stem cells, which usually develop into red blood cells, platelets, and certain types of white blood cells.

How Do Blood Cancers Cause ITP?

In some people with leukemia and lymphoma, the immune system becomes dysregulated. This means it may mistakenly attack healthy cells, including platelets.

The immune system makes proteins called autoantibodies that attach to platelets. These antibody-coated platelets are then removed and destroyed, mainly in the spleen. As platelet levels fall, ITP develops.

Changes in regulatory T cells, a type of immune cell that helps keep the immune system from overreacting, may also play a role. When T cells don’t work properly, the immune system may make more antibodies that target platelets.

Some blood cancers can also keep the bone marrow from making enough platelets, further lowering the platelet count. However, low platelet counts caused by reduced platelet production are different from ITP, which is mainly an immune disorder.

What Tests Help Diagnose ITP Compared With Blood Cancers?

Unfortunately, there’s no one test that can diagnose ITP or rule out other conditions. Doctors instead use a combination of tests to find out what’s causing thrombocytopenia. Because ITP is a diagnosis of exclusion, they first rule out other possible causes, including blood cancers.

Complete Blood Count

A complete blood count (CBC) test measures your red blood cells, white blood cells, and platelets. These results can provide clues to whether your symptoms may be caused by ITP, a blood cancer, or another condition.

Your doctor may also monitor your platelet count over time, but how quickly your platelet count drops doesn’t reliably distinguish ITP from blood cancer. A sudden or gradual drop can have many causes. Doctors also consider your symptoms, medical history, blood smear results, other blood cell counts, and additional test results when making a diagnosis.

Bone Marrow Biopsy

A bone marrow biopsy lets doctors take a closer look at the cells in your bone marrow. During this procedure, a small sample of tissue is taken, usually from the hip bone, and then examined under a microscope.

A bone marrow biopsy helps diagnose blood cancers, including leukemia and lymphoma. This test is also sometimes used to identify ITP and rule out other blood disorders, especially in older adults.

However, research has shown that bone marrow biopsy isn’t usually needed when a person has typical signs of ITP and no other unusual findings. Doctors are more likely to recommend this test if other blood cell counts are abnormal, the blood smear shows unusual cells, the spleen or lymph nodes are enlarged, symptoms suggest another condition, or treatment isn’t working as expected.

Tests To Rule Out Other Causes of Secondary ITP

Secondary ITP can develop not just from blood cancers but also from other medical conditions, including autoimmune diseases and certain infections.

Healthcare providers may recommend testing for autoimmune diseases if you have symptoms that suggest one. For example, if you have joint pain, swelling, or skin rashes, your doctor may order antibody tests to rule out conditions such as lupus or rheumatoid arthritis.

Blood tests may also be used to look for infections linked to ITP, such as:

• Hepatitis C virus
• Helicobacter pylori
• Human immunodeficiency virus (HIV)

How Does Blood Cancer Affect ITP Treatment?

ITP treatment focuses on reducing the immune system’s attack on platelets. Depending on how low your platelet count is and whether you’re bleeding, you may also need treatments to raise your platelet count.

Common treatment options for ITP include:

• Corticosteroids, which reduce immune activity that destroys platelets
• Immunosuppressants, which help calm an overactive immune system
• Intravenous immunoglobulin (IVIG), an infusion of donated antibodies that temporarily slow platelet destruction
• Platelet transfusions, which replace platelets during severe or life-threatening bleeding
• Rituximab, a medication that targets immune cells that produce antibodies involved in platelet destruction
• Splenectomy, surgical removal of the spleen to help stop platelet destruction
• Thrombopoietin receptor agonists, which stimulate bone marrow to make more platelets

Other medicines may be used if ITP doesn’t respond well enough to earlier treatment.

Treatment Options for Blood Cancer and ITP

When you have both ITP and blood cancer, your treatment plan may need to address both conditions. Corticosteroids are often used first for ITP linked to blood cancer. IVIG may be added when doctors need to raise the platelet count quickly.

The best treatment depends on several factors, including your platelet count, bleeding symptoms, cancer activity, previous treatments, and response to therapy.

Some people with CLL may also benefit from a splenectomy. In CLL, the spleen can become enlarged and overactive, causing it to remove platelets faster than the bone marrow can replace them.

Treating Underlying Blood Cancer May Help Manage ITP

Since some blood cancers can trigger secondary ITP, treating the cancer may also improve platelet counts. Treatment depends on the type of blood cancer, how active it is, and your overall health.

Options may include targeted therapy, immunotherapy, chemotherapy, or stem cell transplantation. For CLL and SLL, targeted therapies have largely replaced chemotherapy for many people.

Doctors don’t automatically start blood cancer treatment just because someone develops ITP. Instead, they may treat the cancer if the ITP doesn’t respond to standard treatment or if the cancer itself has progressed enough to require treatment.

Does ITP Affect Your Prognosis With Blood Cancer?

Studies suggest that ITP can affect overall health and outlook in people living with some blood cancers. For example, research has found that people with AML or CLL who also have ITP may be more likely to experience:

• Longer and more costly hospital stays
• Nosebleeds
• Bleeding in the brain that isn’t caused by an injury
• A need for platelet or blood transfusions

Talk with your doctor if you’re concerned about your bleeding risk or notice any new or worsening symptoms. They can evaluate your symptoms and order any tests that may be needed.

Treating both ITP and the underlying cancer can help lower the risk of complications and improve your overall health.