Sorting Through The Confusion Over Leukemia Types

by Jane Ashley

Are you confused about leukemia? Patients and their families may be confused by their “official” diagnosis because it is contains three words and is often referred to by its acronym (an abbreviation of the first letters of the words in the name of an organization or disease – for example, NASA, ATM or COPD).

Leukemia Is Cancer Of White Blood Cells

What is Leukemia?

Leukemia is kind of cancer that originates in our bone marrow, causing abnormal white cells to be produced. Our bone marrow (the spongy, red tissue in our large bones) produces lymphocytes. Lymphocytes are found in our blood, lymph nodes and spleen. Normal lymphocytes fight bacterial and viral infections.

Although leukemia is sometimes considered a childhood cancer, it is far more common in adults over 40. Leukemia is more prevalent in men. Symptoms vary by which type of leukemia a patient has. Common symptoms include:

Bleeding easily or bruising
Bone pain
Chills or fever
Fatigue
Frequent infections
Frequent nosebleeds
Night sweats
Petechiae (tiny red spots on the skin)
Swollen lymph nodes
Weight loss

Childhood Leukemia

Leukemia can be either acute or chronic. The acute kind develops rapidly – these immature cells (called blasts) can’t perform any immune system functions. The chronic kind of leukemia develops in more mature cells and can still carry on some immune functions; these cells reproduce more slowly than the immature blasts.

Types of Acute Leukemia

Acute leukemia develops more quickly. Acute leukemia affects the immature cells, called blasts or stem cells. Because acute leukemia types affect our stem cells, they multiply rapidly — quickly overtaking and crowding out our red cells and our platelets. The growth may be so rapid that acute leukemia may spread to other organs of the body and our central nervous system.

There are two types of acute leukemia.

Acute Lymphocytic Leukemia (ALL). Almost 6,000 people of all ages in the U.S. are diagnosed with ALL annually. Four out of every 10 patients; the remainder are children, with the majority being under the age of 5.

This form of leukemia occurs as several sub-types, depending on which type of lymphocyte is affected. There may also be chromosomal or genetic changes in the cancer cells. The sub-types and cell changes help guide treatment for each patient.

B-Cell Lymphoblastic Leukemia – the most common subtype, accounting for 88 percent of childhood cases and 75 percent of adult cases. This type begins in the immature cells that would become B-cells

T-Cell Lymphoblastic Leukemia – this leukemia occurs in the cells that would become T-cells.

Philadelphia Chromosome Positive Lymphoblastic Leukemia – this uncommon subset happens when two chromosomes (9 and 22) fuse together. This subset is treated in a completely different manner.

Acute Myeloid Leukemia (AML). This type of leukemia affects the immature cells that would develop into neutrophils, one of our infection fighting white cells. They don’t develop as expected leading to a buildup of immature blasts and not enough red blood cells or platelets.
About 21,500 people in the U.S. develop AML annually. Almost 70 percent of patients are children. AML is the second most common leukemia in the U.S.

Symptoms are related to the decrease in number of healthy blood cells. Patients experience anemia, neutropenia (and infections related to extremely low neutrophil counts) and the tendency to bruise easily. Some patients experience all three of these symptoms.

The World Health Organization developed a new classification system of subsets of AML. These subsets help develop an individualized treatment regimen for each AML patient.

Immediate treatment is recommended once a patient is diagnosed with acute leukemia of either type. Treatment options include:
Chemotherapy (either phased or intensive)
Targeted Therapy
Radiation
Stem cell transplant

Types of Chronic Leukemia

The chronic types of leukemia develop more slowly and sometimes produce vague or no symptoms. Chronic types of leukemia are sometimes discovered through regular lab tests as part of an annual physical.

Chronic Lymphocytic Leukemia (CLL). CLL is the most common type of leukemia in adults. Approximately 20,720 adults are diagnosed annually in the U.S. CLL is more common in adults over 50 and is more prevalent in men.

Many patients are asymptomatic. There are two forms of CLL. The slower-growing form may remain stable for years. The faster-growing form eventually causes red blood cell and platelet counts to drop, resulting in anemia, neutropenia or thrombocytopenia.

Vietnam veterans who were exposed to Agent Orange and other herbicides who develop CLL are entitled to VA disability. If you are a Vietnam veteran and think that you may have been exposed to Agent Orange, the VA urges you to apply for compensation at 

Department of Veterans Affairs

Slow-growing CLL might just be watched and monitored if a patient’s CLL is stable. Treatments include chemotherapy, targeted therapy, radiation, surgery and bone marrow or stem cell transplants.

Chronic Myeloid Leukemia (CML). About 9,000 people in the U.S. are diagnosed annually. Half of all patients are over 64. These patients may experience the Philadelphia translocation of genes 9 and 22 just a patients with acute lymphocytic leukemia.

CML has 3 phases:

Chronic – when the bone marrow contains less than 10 percent blasts.
Accelerated – when both the blood and bone marrow contains 10-19 percent blasts.
Blast crisis – a crisis occurs when blast levels reach 20 percent or more in the bone marrow or bone and it is difficult to control the number of white cells. 

Resistant CML – if a patient’s CML doesn’t respond to treatment or comes back after treatment, it’s considered resistant CML.
Without treatment, CML will progress to the accelerated phase and then into the blast crisis phase after 3 or 4 years.

CML is treated with chemotherapy, targeted therapy and immunotherapy.

5-year survival rates for CML patients have dramatically increased — from 22 percent in the mid-1970s to 67 percent for patients diagnosed between 2008 and 2014 — thanks to the development of targeted therapies like imatinib (Gleevec).

Older Men Leukemia

Rare Types of Leukemia

There are a number of uncommon types of leukemia — most of these are rare sub-types of the four most common types of leukemia discussed here. There are several types that are of interest.

Sezary Syndrome. This is a sub-type of T-cell lymphoma that occurs on the skin. It’s slow-growing and is detected by large numbers of lymphoma cells are found in the blood and a reddening of the skin.
Hairy Cell Leukemia. This rare type of chronic leukemia is known by the short, thin projections that protrude from the cells. Treatment is effective — 5 year survival rates are 90 percent.
Large Granular Lymphocytic (LGL) Leukemia. This uncommon form of leukemia is characterized by enlarged lymphocytes that are grainy in appearance.
Chronic Myelomonocytic Leukemia (CMML). Uncommon (only 3 in every 100,000 people) with features of two different kinds of blood cancer.

Other uncommon forms of leukemia include B-cell prolymphocytic leukemia (B-PLL) and T-cell prolymphocytic leukemia (T-PLL).

The Bottom Line …

Leukemia is one of the few types of cancer that affect both children and adults. There are four common types of leukemia – two are acute and require immediate treatment — two are chronic, with some patients watched until their disease progresses to the point of requiring treatment.
Overall-survival rates have quadrupled since 1960. More men have leukemia, and researchers still aren’t sure why. Despite treatment improvements, leukemia is the still the sixth leading cause of death in the U.S. for both men and women.

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