According to the National Cancer Institute, around 1.5 percent of Americans will be diagnosed with leukemia in their lifetime. Leukemia is the most common cancer in children under age 15 and the most common blood cancer in people older than 55 in the United States. In 2021, there were an estimated 508,796 Americans living with leukemia.

Leukemia is a type of blood cancer that begins in the bone marrow (the soft, spongy tissue inside bones) when hematopoietic cells (stem cells that form blood cells) develop abnormalities. These abnormal cells then divide uncontrollably and can invade nearby tissues or spread to other parts of the body, becoming cancerous.

What Causes Leukemia?

Like all cancer, leukemia is caused by genetic mutations (changes in DNA) that make cells divide and grow in an uncontrolled way. Most cancers result from acquired mutations — changes that happen over a person’s life rather than ones they’re born with. However, at least 5 percent of leukemias are hereditary, meaning they’re passed down from a parent.

According to the Leukemia & Lymphoma Society, males and non-Hispanic white people have the highest risk of developing leukemia.

Other risk factors for leukemia include:

• Older age
• High doses of radiation
• Exposure to chemicals such as benzene (found in some industrial processes and cigarette smoke)
• Obesity (having a body mass index, or BMI, of 30 or higher, a measure based on height and weight)
• Certain genetic disorders, such as Down syndrome
• Smoking
• Previous cancer treatment with certain chemotherapy drugs

Read more about risk factors and causes of leukemia.

How Does Leukemia Affect the Body?

Leukemia affects the body in several ways:

• Impaired immune function — The abnormal white blood cells can’t fight infections well, leading to frequent or severe infections.
• Anemia — As leukemia cells crowd out healthy red blood cells, the body may not have enough to carry oxygen, causing tiredness and weakness.
• Easy bleeding or bruising — With fewer healthy platelets (cells that help blood clot), blood may not clot properly, making bruising or bleeding more common.
• Swollen lymph nodes — Leukemia cells may accumulate in lymph nodes (small glands in the immune system), causing them to swell.
• Organ enlargement — In some cases, leukemia cells can collect in organs like the spleen or liver, causing them to enlarge.

What Are the Symptoms of Leukemia?

Symptoms of leukemia can vary by age and type of leukemia. In addition to those effects listed above, some most common symptoms across all types of leukemia include:

• Fatigue
• Shortness of breath
• Fever
• Night sweats
• Bruising or bleeding easily
• Bone pain
• Joint pain
• Frequent infections
• Weight loss (seen more often in older adults with leukemia)

Read more details about symptoms of leukemia.

How Is Leukemia Diagnosed?

There are no screening exams that can catch leukemia early. Sometimes, leukemia can be discovered when a person sees their doctor for symptoms that may be mistaken for common illnesses like the flu. In some cases, it’s found during routine blood tests. When leukemia is suspected, doctors order specific tests to confirm the diagnosis, identify the type of leukemia, and gather details that will help guide treatment options.

How Long Can Leukemia Go Undetected?

How long leukemia goes undetected depends on the type of leukemia and individual factors. Chronic leukemias often develop slowly and may not cause noticeable symptoms for years. In contrast, acute leukemias progress quickly and usually cause symptoms that need treatment sooner.

Once leukemia is suspected, doctors may order the following tests to confirm the diagnosis:

• Physical exam
• Laboratory tests on blood samples, including complete blood count (CBC), blood smear, and blood chemistry
• Cytogenetic analysis to determine specific chromosome abnormalities in leukemia cells
• Bone marrow biopsy or bone marrow aspiration
• Imaging tests such as X-rays, computed tomography (CT), or magnetic resonance imaging (MRI)

Read more about tests to diagnose leukemia.

What Are the Different Types of Leukemia?

Each case of leukemia is either acute or chronic. Acute leukemia grows rapidly and requires immediate treatment, while chronic leukemia grows more slowly and may not require treatment right away. Leukemias are also grouped by the type of blood cells involved and their stage of maturity. Additionally, leukemia may be further classified based on specific genetic changes found during cytogenetic analysis (genetic testing) of the cancer cells.

The four main types of leukemia are:

• Acute lymphoblastic leukemia (ALL) — Also called acute lymphocytic leukemia, a lymphoid cancer that can affect B cells and T cells, types of white blood cells
• Acute myeloid leukemia (AML) — Also called acute myelogenous leukemia, affecting myeloid cells
• Chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) — A B-cell leukemia often found in older adults
• Chronic myeloid leukemia (CML) — Also called chronic myelogenous leukemia, a myeloid cell leukemia

Each of these main types has many subtypes. CLL/SLL cases are assigned stages, whereas CML cases are described by phases. Some rare types of leukemia don’t fit into the main categories above, and certain types may develop from other blood cancers, such as lymphoma or myeloproliferative neoplasms (MPNs).

Read more about types of leukemia and stages of leukemia.

How Is Leukemia Treated?

Many types of treatment are used to fight leukemia. Depending on the stage and type of leukemia you have, standard treatment options may include:

• Chemotherapy — Uses drugs to kill cancer cells
• Targeted therapy — Attacks specific weaknesses in cancer cells
• Immunotherapy — Boosts the body’s immune system to help recognize and attack cancer cells, sometimes by producing antibodies that specifically target them
• Radiation therapy — Uses high-energy rays to kill cancer cells
• Stem cell transplant — Replaces diseased bone marrow with healthy hematopoietic stem cells
• Cell therapy — Modifies T cells (a type of white blood cell that fights infections) to target leukemia cells

Some people with leukemia choose to join clinical trials, which are research studies to test new treatments.

Your hematologist/oncologist (blood cancer specialist) will recommend treatment options based on several different factors, including which type of leukemia you have, your age, and your overall health. Treatments may be used alone (called monotherapy) or combined into a treatment plan.

In acute leukemia, treatment needs to start immediately. Chronic leukemia grows more slowly and may not require treatment right away, an approach sometimes called “watch and wait.” The goals of leukemia treatment may also differ from case to case. A cure may be possible for many cases of acute leukemia, but treatments for chronic leukemia may focus on achieving remission (no signs of cancer) and preventing relapses, or simply slowing the growth of cancer.

Read more about treatments for leukemia.

How Do Other Health Conditions Affect Leukemia?

When someone has more than one health condition at the same time, the conditions are referred to as comorbidities. Comorbid conditions can affect leukemia in different ways. If you have leukemia along with other health conditions, these comorbidities may reduce your body’s tolerance for leukemia treatment and limit your treatment options. Because of this, having comorbidities can also impact your prognosis (the likely outcome of your illness).

Some health conditions may also be more likely to develop after leukemia treatment. Your doctor can help you understand your specific risk factors for these related conditions and suggest steps to help lower your risk.

Read more about other health conditions related to leukemia.

What Is the Prognosis for Leukemia? Can It Be Cured?

Advances in leukemia treatment have greatly improved survival rates. The overall five-year relative survival rate for leukemia in the U.S. is 67 percent. This means around 2 out of 3 people in the U.S. diagnosed with leukemia are still alive after five years. However, prognosis can vary widely depending on the type of leukemia, age, overall health, and how well a person responds to treatment.

While some types of leukemia can be cured, others may be managed as chronic conditions, focusing on preventing relapses or slowing cancer growth. Your oncology team can provide more specific information about your individual prognosis and treatment options.

If you or a loved one has been diagnosed with leukemia, working closely with your health care team is essential. They can help you understand your specific situation and make informed decisions about your care.

Talk With Others Who Understand

MyLeukemiaTeam is the social network for people with leukemia and their caregivers. On MyLeukemiaTeam, more than 20,000 members come together to ask questions, give advice, and share their experiences with others who understand life with different forms of leukemia.

Are you living with leukemia? Share your experience in the comments below, start a conversation by posting on your Activities page, or connect with like-minded members in Groups.