Diagnosing Acute Myeloid Leukemia

There are several types of leukemia—including acute lymphoblastic leukemia, chronic myelogenous leukemia, and chronic lymphocytic leukemia—and their treatments may differ. Acute myeloid leukemia, commonly known as AML, is a cancer that begins in immature white blood cells called myeloblasts. These cells are located in the bone marrow, the spongy tissue inside bones.

In this type of fast-growing blood cancer, the body makes high levels of cancerous immature blood cells, which build up in the bone marrow and the blood. They interfere with the growth of healthy blood cells, including white blood cells, which fight infection; red blood cells, which carry oxygen throughout the body; and platelets, which help blood clot.

People over age 60 are more likely to develop acute myeloid leukemia, although it can occur in adults at any age, as well as children. More men than women are affected.

Risk factors for AML include a history of smoking, especially after age 60; chemotherapy or radiation therapy for other cancers; exposure to radiation; long-term exposure to certain industrial chemicals, such as benzene; and myelodysplastic syndromes, a condition in which the bone marrow fails to produce healthy blood cells.

There are several subtypes of AML, which are classified in terms of the maturity of the leukemia cells and the type of blood cell most affected, meaning white or red blood cells or platelets. Determining which type of AML a person has helps doctors recommend the most effective treatment.

Symptoms of Acute Myeloid Leukemia

In people with AML, high levels of cancerous myeloblasts, or immature white blood cells, prevent normal white and red blood cells and platelets from growing in the bone marrow. This leads to symptoms such as fatigue and weakness, fever and other symptoms of infection, a tendency to bruise easily, and unexplained weight loss.

As the myeloblasts accumulate in the bone marrow, they spill into the blood, hindering blood flow, which leads to blocked blood vessels, atypical bleeding from the nose or gums, and headache, and may lead to stroke or heart attack.

Some of these symptoms can indicate other health conditions, so your doctor takes a medical history to help determine your symptoms and performs a physical exam. He or she also orders blood tests, which can reveal low levels of red and white blood cells and platelets—signs of acute myeloid leukemia.

Diagnostic Tests

NYU Langone hematologist–oncologists—doctors who treat blood disorders such as blood cancers—perform several tests to identify acute myeloid leukemia. The results help doctors determine the type of leukemia a person has and the severity of the condition.

Blood Tests

NYU Langone specialists take a sample of your blood to check the levels of white and red blood cells and platelets. They also measure the amount of hemoglobin, the protein in red blood cells that carries oxygen, because low levels can indicate decreased production as happens with AML.

Bone Marrow Aspiration and Biopsy

Leukemia starts in the bone marrow, so your doctor examines the blood cells there. After injecting a local anesthetic to numb the lower back, he or she inserts two needles into the pelvic bone and removes a sample of bone marrow fluid with one and a tissue sample with the other. The doctor sends the specimens to a pathologist, a specialist who studies diseases under a microscope.

The pathologist also examines these cells using an instrument called a flow cytometer. This tool can detect certain proteins on the surface of cells that reveal the type of blood cell and whether it is cancerous.

Lumbar Puncture

If your doctor suspects the cancer has spread to the central nervous system, he or she may perform a lumbar puncture. This procedure is done at the hospital using a local anesthetic. A specialist inserts a small needle into the lower back to withdraw spinal fluid, which is examined in a laboratory.

If cancer cells are present, you may require intrathecal therapy, in which chemotherapy drugs are administered directly into the spinal fluid.

Chromosome Analysis

Chromosomes are the components of a person’s cells that carry genetic information. Knowing whether the cancer cells carry any abnormal chromosomes enables your doctor to better determine your prognosis. Then he or she performs chromosome analysis tests to identify the irregularities.

At NYU Langone, your doctor orders a test called fluorescence in situ hybridization (FISH), which can detect chromosomal changes that typically go undetected by a conventional chromosomal analysis. This testing is done to look for genetic mutations, or changes, that help determine the appropriate treatment.

Your doctors may also perform a reverse transcription-polymerase chain reaction test to look for certain genetic mutations and translocations—when genes or parts of genes switch places on the chromosomes of leukemia cells. These genetic mistakes can cause the cells to act aggressively, and analyzing them can help doctors determine the severity of the condition and its treatment. Acute promyelocytic leukemia, a type of AML that is treated differently than the others, can be diagnosed quickly with this test.

Flow Cytometry

Flow cytometry detects proteins that are present on the surface of leukemia cells. Different types of cancer express different types of proteins, also called tumor markers. In this test, bone marrow samples retrieved during bone marrow aspiration are tested in a laboratory. The results help doctors to determine the type of leukemia present in the body and to choose the best treatments for you.

Molecular Profiling Studies

Molecular studies are laboratory tests that identify changes in DNA. In these tests, pathologists use microscopes to analyze tissue samples collected during bone marrow aspiration. This allows doctors to gather information about the cancer, such as its likelihood for responding to certain treatments.