Leukemia

Our blood has many tiny parts.

These parts help us stay well. Sometimes, bad cells grow in the bone marrow. This is called leukemia.

These bad cells crowd out the good ones. This can make a person feel very tired. It can also cause easy bruises or a fever. Doctors use blood tests to find it. Many people get better with help from doctors.

We can learn more about how our bodies work.

Leukemia is a group of blood cancers.

These cancers usually start in the bone marrow. The marrow is the soft part inside bones. It makes our blood cells. In leukemia, the marrow makes too many abnormal cells. These cells are not fully grown. Doctors call them blasts.

These bad cells crowd out the healthy ones. This can cause many problems. A person might feel very tired or have a fever. They might also bruise easily or bleed. This happens because there are not enough normal blood cells.

There are four main types of leukemia. Some are called acute. Acute means they grow very fast. These need quick help from doctors. Others are called chronic. Chronic means they grow more slowly over months or years.

Doctors use blood tests to find leukemia. They may also use a bone marrow biopsy. This is a test to look at the marrow. Treatments can include chemotherapy or radiation. Some people also get a bone marrow transplant. Many people get better with these treatments.

Leukemia is a group of blood cancers that usually begins in the bone marrow.

The bone marrow is the soft part inside your bones. It is where your body makes blood cells. In leukemia, the marrow produces too many abnormal blood cells. These cells are not fully developed. Doctors call these immature cells "blasts." Because these abnormal cells crowd the marrow, the body cannot make enough healthy cells. This can lead to many different health problems.

How the disease works depends on how fast the cells grow. There are two main ways it progresses: acute and chronic. Acute leukemia involves a rapid increase in immature blood cells. This type needs immediate treatment because the cells spread quickly. Chronic leukemia is different because the cells grow more slowly. These abnormal cells might build up over months or even years. In some chronic cases, doctors might use "watchful waiting" to monitor the person before starting treatment.

Doctors classify leukemia into four main types based on the cells involved. The first two are acute lymphoblastic leukemia (ALL) and acute myeloid leukemia (AML). The other two are chronic lymphocytic leukemia (CLL) and chronic myeloid leukemia (CML). ALL is the most common type in young children. However, over 90% of all leukemia cases are diagnosed in adults. For adults, CLL and AML are the most common types. Different types affect different parts of the blood, like the cells that fight infection or the cells that help blood clot.

Finding leukemia can be done through blood tests or a bone marrow biopsy.

Treatment often uses a combination of tools. These include chemotherapy, radiation therapy, and targeted therapy. Some people may also need a bone marrow transplant. Success often depends on the type of leukemia and the person's age. In the United States, the five-year survival rate was 68% between 2015 and 2021. For children under 15, the survival rate can be higher than 60% or even 90%.

Leukemia affects people all over the world in different ways. In 2015, leukemia was present in 2.3 million people globally. It caused 353,500 deaths that same year. In 2012, 352,000 people newly developed the disease. While it is the most common cancer in children, it occurs more often in the developed world. You can think of the blood like a busy highway. Healthy cells are like cars moving smoothly to do important jobs. Leukemia is like having too many broken cars blocking the road so the good ones cannot pass.

Leukemia is a complex group of blood cancers that primarily originate in the bone marrow.

The disease is characterized by the production of high numbers of abnormal, immature blood cells. These cells are often called blasts or leukemia cells because they are not fully developed. Because these abnormal cells crowd the bone marrow, the body struggles to produce healthy, functional cells. This lack of normal blood cells leads to various medical symptoms. These symptoms include fatigue, fever, bone pain, and an increased risk of infections.

People may also experience easy bruising or bleeding due to low platelet counts.

The way leukemia progresses depends on the speed of cell growth. Doctors divide the disease into acute and chronic forms. Acute leukemia involves a rapid increase in the number of immature blood cells. These malignant cells accumulate quickly and can spill into the bloodstream to affect other organs. Because of this rapid progression, acute leukemia requires immediate medical treatment. In contrast, chronic leukemia is characterized by the buildup of relatively mature but still abnormal cells. This process typically takes months or even years to progress. Because chronic forms move more slowly, doctors sometimes use watchful waiting to monitor the patient before starting therapy.

Scientists further classify leukemia based on the specific type of cell affected. This creates four main categories. Lymphoblastic or lymphocytic leukemias occur when the cancerous change happens in cells that normally become lymphocytes. Lymphocytes are part of the immune system and help fight infections. Most of these involve a subtype called B cells. Myeloid or myelogenous leukemias affect cells that normally become red blood cells, certain white cells, or platelets. By combining these two classifications, doctors identify the four major types: acute lymphoblastic leukemia (ALL), acute myeloid leukemia (AML), chronic lymphocytic leukemia (CLL), and chronic myeloid leukemia (CML).

Each of these four types has unique characteristics and impacts different age groups. Acute lymphoblastic leukemia (ALL) is the most common type found in young children. However, 80% of deaths from ALL actually occur in adults. Chronic lymphocytic leukemia (CLL) mostly affects adults over the age of 55 and almost never affects children. Two-thirds of people with CLL are men. Acute myeloid leukemia (AML) is much more common in adults than in children and is more frequent in men. Finally, chronic myeloid leukemia (CML) occurs mainly in adults, though a very small number of children can develop it.

While the exact cause of leukemia is still unknown, several factors are believed to play a role. It is thought to be a combination of genetic factors and environmental factors. Some known risk factors include smoking, ionizing radiation, and exposure to petrochemicals like benzene. A history of prior chemotherapy or having Down syndrome can also increase risk. People with a family history of the disease are at a higher risk as well. Diagnosis is usually achieved through blood tests or a bone marrow biopsy to look for abnormal cells under a microscope.

Medical outcomes for leukemia have improved significantly in the developed world. In the United States, the five-year survival rate was 68% between 2015 and 2021. For children under 15 in first-world countries, the survival rate can be greater than 60% or even 90%, depending on the specific type. For infants diagnosed under age one, the survival rate is approximately 40%. If a child with acute leukemia remains cancer-free for five years, the cancer is unlikely to return. However, the disease remains a major global health issue. In 2015, leukemia was present in 2.3 million people worldwide and caused 353,500 deaths.

Treatment strategies vary depending on the type of leukemia and the patient's age. Common treatments include chemotherapy, radiation therapy, and targeted therapy. Some patients may also require a bone marrow transplant. Supportive and palliative care are also provided to help manage symptoms. Because leukemia affects the hematopoietic and lymphoid systems, it is part of a broader group of tumors affecting blood and immune tissues. Understanding these different cell types and growth rates helps doctors choose the most effective way to manage the disease.