What is Erythroleukemia & How is it Treated?

Erythroleukemia is a cancer of blood and bone marrow and is a rare subtype of acute myeloid leukemia. Only 3-5% of cases of acute myeloid leukemia are erythroleukemia.^{(1, 2)}

Acute myeloid leukemia begins in the bone marrow. It is due to the presence of abnormal blood-forming cells known as myeloid cells. It spreads from bone marrow to the blood and from blood to the other parts of the body.

Erythroleukemia is further categorized into:

• Pure Erythroid Leukemia (PEL): In this, specific marrow cells consist of at least 80% of the particular type of erythroblasts.
• Erythroid/Myeloid Leukemia (EML): In this erythroid cells consist of 50% or more marrow cells and myeloblast consist of 20% of non-erythroid cells.

There is a reduction in blood production in erythroleukemia, which can lead to lower white blood cell count, and decreased platelets and red blood cells. These changes may lead to:

• Fatigue
• Night sweats
• Malaise
• Weight loss
• Pain in joint and bone
• Fever
• Bruising

There is a range of blood tests and bone marrow tests that can be done to diagnose acute myeloid leukemia or its subtypes like erythroleukemia. A blood or bone marrow sample is taken for testing in the laboratory.

The tests include:

• Complete Blood Count (CBC): This involves taking a blood sample to test for red blood cells, white blood cells, and platelets.
• Peripheral Blood Smear: In this test, the blood sample is taken to check the size, shape, and amount of red blood cells, white blood cells, and platelets. It also checks for leukemia blast cells.
• Bone Marrow Samples: In this test, a liquid bone marrow sample or small section of bone containing marrow is taken to check for unusual changes. The sample is mostly taken from the hip bone.
• Flow Cytometry: This test identifies markers on cells, which help in comparing cancer cells to normal cells present in blood and bone marrow. It is also known immunophenotyping test.
• Molecular Tests: Tests are done to check chromosomes and genes in the leukemia cells.

Tests are also done to check for a person’s overall health.

The treatment for erythroleukemia involves chemotherapy and stem cell therapy. Chemotherapy is the first option for treating this condition. In it, drugs are used that target cancer cells to destroy them and prevent their multiplication. The drugs in chemotherapy are given either orally or intravenously.

Chemotherapy drugs can lead to side effects including:

• Fatigue
• Increased risk of infection
• Appetite loss
• Nausea and vomiting
• Hair loss
• Rash
• Mouth sores
• Changes in nail and skin

A stem cell transplant is an option in which the doctor replaces cancer cells with stem cells. These are suitable for people with erythroleukemia, depending on its stage and how it is spread. All suffering from erythroleukemia do not qualify for stem cell transplant as it is an intensive process and involves many risks. The risk includes:

• Lung problem
• Hepatic Veno-occlusive disease
• Bleeding
• Infection
• Graft-versus-host disease
• Graft failure

According to an article published in 2018, treating erythroleukemia can be difficult and people’s response to the therapies can be very poor.⁽²⁾ It is observed that people live for 8-9 months after the initial diagnosis.⁽³⁾ There are also complications due to chemotherapy drugs which include relapse and toxicity.⁽¹⁾

The outlook of erythroleukemia also depends on other factors including:

• Chromosomal abnormalities
• Infection
• White blood cell counts
• Genetic mutation
• Age and general health
• Another blood disorder
• Markers for leukemia

Erythroleukemia is a type of acute myeloid leukemia and is known to affect males mostly. It is important to identify the subtypes of acute myeloid leukemia to diagnose erythroleukemia. A doctor recommends those with erythroleukemia to enroll in trials to study new treatment options. It is therefore important to speak with the doctor about the risk and benefits of joining a trial.