What To Know About the Most Common Leukemia in Adults

Acute myelogenous leukemia (AML), also known as acute myeloid leukemia, is a type of cancer that starts in your bone marrow (the soft, spongy tissue inside the bones that makes blood cells). AML is rare, affecting about 4 in 100,000 people every year. It’s most likely to affect older adults, but it can also affect children.

With AML, the bone marrow makes too many immature white blood cells. These abnormal cells, called leukemia cells, don’t develop into normal white blood cells. Instead, they multiply and leave little room for healthy blood cells to develop.  

AML tends to spread very quickly. AML symptoms include fever, easy bruising, fatigue, and bone or joint pain. Treatment for AML has improved over the years, and the sooner it is diagnosed and treated, the better the outcomes may be.

There are several subtypes of AML, classified based on the cancer cells’ shape and gene changes. AML doesn’t cause tumors, so healthcare providers don’t use the tumor staging system to classify type or severity, like with other cancers.

Experts have updated how they classify AML to help improve diagnosis and treatment. There are several classification systems healthcare providers may use when determining which type of AML. Each classification system below categorizes AML into different subtypes: 

• French-American-British (FAB) classification: An older system based on how leukemia cells look under the microscope and their level of maturity. Based on the development of the leukemia cells, this system groups AML into eight types (M0-M7).
• World Health Organization (WHO) classification: A newer system focusing on genetic changes and AML development. It includes categories like AML with specific genetic mutations, AML linked to other blood disorders, and treatment-related AML.
• European LeukemiaNet (ELN) 2022 guidelines: These latest guidelines include changes to how many abnormal cells need to be present for diagnosis and add new genetic subtypes to the list.

As leukemia cells crowd out healthy blood cells, including white blood cells (which protect against infection), red blood cells (which carry oxygen), and platelets (which help blood clot), noticeable symptoms can include: 

• Fever that persists or comes and goes
• Extreme fatigue or weakness that doesn’t improve with rest
• Shortness of breath
• Pale skin due to anemia
• Frequent infections
• Easy bruising or bleeding, including bleeding gums or heavy menstrual periods
• Tiny red spots under the skin, known as petechiae, caused by bleeding
• Bone or joint pain, especially in your ribs or joints
• Swollen lymph nodes in your neck, armpit, or groin
• Loss of appetite or feeling full quickly when eating
• Unintentional weight loss
• Headaches or vision changes

Experts believe that changes in the DNA of bone marrow cells cause AML. DNA is genetic material that tells the cells how to grow and function. These changes, called genetic mutations, cause bone marrow cells to grow and divide too quickly.

Experts don’t fully understand why these genetic mutations happen. They’re often acquired, meaning they occur during your lifetime and aren’t passed down from your parents. These genetic changes tend to happen more frequently as we age, which may help explain why AML is more common in older adults.

Some of these acquired DNA changes occur without a clear cause, but exposure to things in the environment and certain lifestyle factors may play a role.

Risk Factors

Several factors may increase the chances of developing AML:

• Age: AML becomes more common with age, with most cases occurring after age 65.
• Sex: Men are slightly more likely than women to develop AML.
• Smoking: Exposure to certain cancer-causing chemicals found in tobacco smoke increases your risk of developing AML.
• Previous cancer treatment: Radiation therapy and certain chemotherapy medications may increase the risk.
• Exposure to certain chemicals: AML may be more likely after long-term exposure to benzene and other chemicals.
• Blood disorders: Some blood disorders, like myelodysplastic syndrome, can develop into AML.
• Genetic disorders: Certain conditions, such as Down syndrome and Klinefelter syndrome, may increase the risk of AML.
• Family history: Having a close relative, like a parent or sibling, with AML slightly increases your risk, though most cases of AML aren’t inherited.

If your healthcare provider suspects you have AML based on your symptoms, they’ll generally start the diagnosis process by reviewing your medical history and doing a physical exam. Your healthcare provider may request a combination of tests to confirm the diagnosis and determine the subtype of AML. 

Standard tests healthcare providers use to diagnose AML and its type include:

• Complete blood count (CBC): This blood test measures the levels of red blood cells, white blood cells, and platelets in your blood to check for abnormalities.
• Peripheral blood smear: A sample of your blood is examined under a microscope to look for abnormal cells, including immature cells that shouldn’t normally be in the bloodstream.
• Bone marrow biopsy: Your healthcare provider may collect a sample of your bone marrow, usually from your hip bone, to check for leukemia cells.
• Cytogenetic analysis: This test is done on a blood sample or bone marrow sample. It looks for specific DNA changes in the leukemia cells that can help determine the AML subtype.
• Lumbar puncture: A sample of fluid is taken from the spine. It’s performed to check if leukemia cells have spread to the fluid surrounding the brain and spinal cord, especially if you have symptoms like headaches or confusion.
• Imaging tests: Computed tomography (CT) scans, X-rays, or ultrasounds may help your healthcare provider check if AML has affected organs like your liver, spleen, or lymph nodes.

The main goal of AML treatment is to destroy the leukemia cells and help normal blood cells grow. AML progresses quickly, and treatment usually needs to start very soon after diagnosis. 

Treatment typically happens in phases: Induction (first intense treatment to achieve remission, a period where symptoms go away), consolidation (additional treatment to kill remaining hidden cancer cells), and sometimes maintenance therapy (ongoing lower-dose treatment to prevent cancer from coming back).

The type of treatment received typically depends on several factors, including your age, overall health, and which subtype of AML you have. Most people will receive a combination of the following:

• Chemotherapy: This treatment uses medications that kill fast-growing cells throughout your body, including cancer cells.
• Targeted therapy: Medications that attack specific genetic changes in leukemia cells to stop their growth.
• Stem cell transplant: Also called a bone marrow transplant, this treatment replaces cancerous bone marrow cells with healthy donor cells. After intense chemotherapy, it can help rebuild your immune system (your body’s defenses).
• Clinical trials: Research studies testing new treatments that might work better than standard options. Many advances in AML treatment have come from clinical trials.

Throughout treatment, you may need blood tests and bone marrow exams to check how well the treatment works and make adjustments as needed.

Supportive Care

If AML treatments aren’t working, your healthcare team may recommend supportive care. This type of treatment focuses on managing your symptoms and improving your quality of life rather than curing the disease.

For example, you might receive less intensive chemotherapy. You may also have pain management, blood transfusions, and other supportive measures to help you feel more comfortable.

Untreated AML or AML that doesn’t respond well to treatment can lead to serious health effects and conditions. These may include:

• Severe infections: With too few healthy white blood cells, even minor infections can quickly become dangerous.
• Bleeding problems: Low platelet counts prevent proper blood clotting, causing excessive bleeding.
• Anemia: Reduced red blood cells can cause extreme fatigue, weakness, and shortness of breath.
• Leukostasis: A buildup of leukemia cells can thicken your blood, potentially blocking small blood vessels and increasing the risk of stroke.
• Organ damage: AML cells can spread to organs like your brain, liver, and spleen, causing swelling, pain, and problems with how these organs work.

AML spreads quickly and can be difficult to treat, especially in older adults. Recent advances in treatment, including targeted therapies, have improved outcomes. Getting a diagnosis and starting treatment early also play an important role.

To help you manage the emotional and physical challenges of living with AML, consider joining a support group, talking to a mental health counselor, or working with a palliative care team.

If your cancer goes into remission, regular check-ups with your healthcare provider are important to watch for any signs the cancer might be coming back.