Leukemia is a type of cancer that affects the blood and bone marrow, where blood cells are formed. All types of leukemia cause rapid, uncontrolled growth of abnormal bone marrow and blood cells.

The main differences between the types include how fast the disease progresses and the types of cells it affects.

There are four main types of leukemia, which we describe in detail below:

Lymphocytic leukemia affects the lymphocytes, a type of white blood cell. Myeloid leukemia can affect the white blood cells, red blood cells, and platelets.

According to the National Cancer Institute, roughly 1.5% of people in the United States will receive a leukemia diagnosis at some point.

In this article, explore the four main types, their symptoms, the treatment options available, and the outlook.

The full name of this type of cancer is acute lymphocytic leukemia, and acute means that it grows quickly. Lymphocytic means that it forms in underdeveloped white blood cells called lymphocytes.

The disease starts in the bone marrow, which produces stem cells that develop into red and white blood cells and platelets.

In a healthy person, the bone marrow does not release these cells until they are fully developed. In someone with ALL, the bone marrow releases large quantities of underdeveloped white blood cells.

There are several subtypes of ALL, and the subtype may influence the best course of treatment and the prognosis.

One subtype is B-cell ALL. This begins in the B lymphocytes, and it is the most common form of ALL in children.

Another subtype is T-cell ALL. It can cause the thymus, a small organ at the front of the windpipe, to become enlarged, which can lead to breathing difficulties.

Overall, because ALL progresses quickly, swift medical intervention is key.

As research from 2020 acknowledges, healthcare providers still do not know what causes ALL. It may occur due to genetic factors or exposure to:

Although genetic factors may play a role, ALL is not a familial disease.

Learn more about ALL here.

ALL is the most common form of leukemia in children.

The risk of developing it is highest in children under 5 years old. The prevalence slowly rises again in adults over 50.

ALL symptoms can be nonspecific difficult to distinguish from those of other illnesses.

They may include:

In a person with AML, the bone marrow makes abnormal versions of platelets, red blood cells, and white blood cells called myeloblasts.

The full name of this disease is acute myeloid leukemia, and acute refers to the fact that it is fast-growing.

It forms in one of the following types of bone marrow cell:

Doctors classify AML by subtype, depending on:

AML can be difficult to treat and requires prompt medical attention.

Learn more about AML here.

The most common risk factor is myelodysplastic syndrome, a form of blood cancer that keeps the body from producing enough healthy blood cells.

Other factors that increase the risk of developing AML include:

Most people who develop AML are over 45. It is one of the most common types of leukemia in adults, though it is still rare, compared with other cancers.

It is also the second most common form of leukemia in children.

Symptoms of AML can vary and may include:

CLL is the most common form of leukemia among adults in the U.S. and other Western countries.

There are two types. One progresses slowly, and it causes the body to have high levels of characteristic lymphocytes, but only slightly low levels of healthy red blood cells, platelets, and neutrophils.

The other type progresses more quickly and causes a significant reduction in levels of all healthy blood cells.

In someone with CLL, the lymphocytes often look fully formed but are less able to fight infection than healthy white blood cells. The lymphocytes tend to build up very slowly, so a person might have CLL for a long time before experiencing symptoms.

Learn more about CLL here.

Genetic factors are the most likely cause. Others might include:

CLL is rare in children. It typically develops in adults aged 70 or over. However, it can affect people as young as 30.

CLL typically causes no early symptoms. When symptoms are present, they may include:

Also, 5090% of people with CLL have swollen lymph nodes.

CML is a slow-growing type of leukemia that develops in the bone marrow.

The full name of CML is chronic myeloid leukemia. As the American Cancer Society explain, a genetic change takes place in the early forms of the myeloid cells, and this eventually results in CML cells.

These leukemia cells then grow, divide, and enter the blood.

CML occurs due to a rearrangement of genetic material between the chromosomes 9 and 22.

This rearrangement fuses a part of the ABL1 gene from chromosome 9 with the BCR gene from chromosome 22, called the Philadelphia chromosome. The result of this fusion is called BCR-ABL1.

BCR-ABL1 produces a protein that promotes cell division and stops apoptosis, the process of cell death, which typically removes unneeded or damaged cells.

The cells keep dividing and do not self-destruct, resulting in an overproduction of abnormal cells and a lack of healthy blood cells.

This occurs during the persons lifetime and is not inherited.

CML typically affects adults. People aged 65 and older make up almost half of those who receive a CML diagnosis.

The symptoms of CML are unclear, but they may include:

The symptoms may vary, depending on the type of leukemia. Overall, a person should get in touch with a doctor if they experience:

Learn more about the symptoms of leukemia here.

Treatment for ALL typically involves three basic phases: induction, consolidation, and maintenance. We describe these in detail below.

Treatment for AML involves the first two phases. The induction phase may include treatment with the chemotherapy drugs cytarabine (Cytosar-U) and daunorubicin (Cerubidine) or idarubicin (Idamycin). The doctor may also recommend targeted drugs.

The goal of this phase is to kill the leukemia cells, causing the cancer to go into remission, using chemotherapy.

The doctor may recommend:

People having chemotherapy may need to see their doctors frequently and spend time in the hospital, due to the risk of serious infections and complications.

This phase of the treatment lasts for about 1 month.

Even if the treatment so far has led to remission, cancer cells may be hiding in the body, so more treatment is necessary.

The consolidation phase may involve taking high doses of chemotherapy. A doctor may also recommend targeted drugs or stem cell transplants.

This phase, consisting of ongoing chemotherapy treatments, usually lasts for 2 years.

Since CLL tends to progress slowly, and its treatment can have unpleasant side effects, some people with this condition go through a phase of watchful waiting before starting the treatment.

For a person with CML, the focus is often on providing the right treatment for the phase of the illness. To do this, a doctor considers how quickly the leukemia cells are building up and the extent of the symptoms. Stem cell transplants can be effective, but further treatment is necessary.

Overall, the initial treatment tends to include monoclonal antibodies, targeted drugs, and chemotherapy.

If the only concern is an enlarged spleen or swollen lymph nodes, the person may receive radiation or surgery.

If there are high numbers of CLL cells, the doctor may suggest leukapheresis, a treatment that lowers the persons blood count. This is only effective for a short time, but it allows the chemotherapy to start working.

For people with high-risk disease, doctors may recommend stem cell transplants.

A persons prognosis depends on the type of leukemia.

Learn more about survival rates for people with leukemia here.

About 8090% of adults with ALL experience complete remission for a while during treatment. And with treatment, most children recover from the disease.

Relapses are common in adults, so the overall cure rate is 40%. However, factors specific to each person play a role.

The older a person is when they receive an AML diagnosis, the more difficult it is to treat.

More than 25% of adults who achieve remission live for 3 years or more after treatment for AML.

A person may live for a long time with CLL.

Treatments can help keep the symptoms under control and prevent the disease from spreading. However, there is no cure.

Stem cell transplants can cure CML. However, this treatment is very invasive and is not suitable for most people with CML.

The United Kingdoms National Health Service estimate that 70% of males and 75% of females live for at least 5 years after receiving a CML diagnosis.

The earlier a person receives the diagnosis, the better their outlook.

Leukemia is a type of cancer that affects the blood and bone marrow. It can affect people of all ages.

There are four main types of leukemia. They differ based on how quickly they progress and the types of cells they affect.

Treatments for all types of leukemia continue to improve, helping people live longer and more fully with this condition.

Excerpt from:
Types of leukemia: Prevalence, treatment options, and prognosis - Medical News Today