Leukemia is a cancer of certain white blood cells, located in the bone marrow where the cells are generated. As the disease progresses, the leukemic white blood cells swamp out other healthy blood cells. The disease causes failure of the blood system. Every year, in the United States, over 60,000 new patients are diagnosed with leukemia. Over 24,000 patients die from leukemia annually.
Like other cancers, there are many kinds of leukemia. The most common leukemias are four types, classified as chronic or acute, and myeloid or lymphoblastic (lymphocytic). Chronic leukemias tend to develop over several years whereas acute leukemias are more aggressive and develop over months. Myeloid or lymphoblastic leukemia refer to the specific types of white blood cells involved in the leukemia.
The different types of leukemias are associated with different symptoms, prognoses, treatments, and genetic causes. Part of making a correct diagnosis involves analyzing patients blood cells under a microscope after chemical staining, called a “blood smear”. Different leukemias are associated with different visual features of blood cells, such as their shape, color upon staining, and size.
Common Types Of Leukemia
There are several different types of leukemia, the most common ones are:
- Acute Myeloid Leukemia (AML)
- Acute Lymphoblastic/Lymphocytic Leukemia (ALL)
- Chronic Myeloid Leukemia (CML)
- Chronic Lymphoblastic/Lymphocytic Leukemia (CLL)
Other types of Leukemia include:
- Myeloproliferative Neoplasms (MPN)
- Acute Promyelocytic Leukemia (APL)
- Myelodysplastic Syndromes (MDS)
- Systemic Mastocytosis (SM)
- Hairy Cell Leukemia (HCL)
Acute Myeloid Leukemia
Acute Myeloid Leukemia (AML), also known as Acute Myelocytic or Myelogenous Leukemia, is a cancer of the blood cells in the Myeloid blood cell lineage. AML is caused by abnormal Myeloid Blasts, or Myeloblasts, produced by the Myeloid progenitors in the bone marrow. Myeloblasts normally develop into healthy red and white blood cells, and platelets which help stop bleeding by forming clots. Cell types produced by Myeloid progenitors include monocytes, macrophages, neutrophils, basophils, eosinophils, erythrocytes, and megakaryocytes.
With Acute Myeloid Leukemia, the Myeloblasts do not develop into healthy cells, instead they develop into immature, mutated white cells. These abnormal cells are less effective at fighting bacteria, infections and viruses. As these immature cells increase, less healthy cells are produced meaning the body cannot defend itself.
Acute Myeloid Leukemia is diagnosed when the abnormal blood cells are mostly monocytes or granulocytes. Monocytes are a type of large white blood cell, these cells help the body fight infections and bacteria. Granulocytes are also white blood cells that help fight infections and allergic reactions. AML most commonly attacks these categories of cells.
Despite being one of the most common forms of Leukemia, Acute Myeloid Leukemia (AML) is still a relatively rare form of Leukemia that is more common in adults, but does affect children also. AML is a very aggressive form of Leukemia and progresses very quickly, early detection is crucial so that treatment can begin immediately.
Acute Myeloid Leukemia was the type of Leukemia that Peter was diagnosed with in 2018. The disease was completely missed in a standarad blood test just one month before he was diagnosed as terminal.
The American Cancer Society's estimates for leukemia in the United States for 2019 are:
- About 21,450 new cases of acute myeloid leukemia (AML). Most will be in adults.
- About 10,920 deaths from AML. Almost all will be in adults.
Acute Lymphoblastic Leukemia
Acute Lymphoblastic Leukemia (ALL), also known as Acute Lymphocytic Leukemia, is a cancer that affects the Lymphoid blood cell lineage. Unlike AML, ALL only affects the white blood cells, namely, Lymphocytes. Lymphocytes include B Cells, T Cells and NK (Natural Killer) cells. ALL is caused by Lymphoid Blasts, or Lymphoblasts, developing into immature Lymphocytes, and an abnormal amount of these immature Lymphocytes are produced. Lymphocytes are white blood cells and play a very important role in the immune system helping to fight off diseases.
Like with AML, these cells begin life as stem cells in the bone marrow, which is responsible for producing red and white blood cells, and platelets. Lymphoblasts are released prematurely before they are fully formed, and are not as effective at fighting infections. Before long, they overcrowd healthy blood cells.
Acute Lymphoblastic Leukemia is most commonly found in children, and is the most common form of child cancer, with around 3000 cases a year in the US alone. Like Acute Myeloid Leukemia, although common, it is still quite rare. In both children and adults, early detection is criticial. Treatment must start immediately due to the aggressiveness of the cancer.
Acute Lymphoblastic Leukemia is diagnosed when the abnormal blood cells are lymphocytes.
The American Cancer Society’s estimates for acute lymphocytic leukemia (ALL) in the United States for 2019 (including both children and adults) are:
- About 5,930 new cases of ALL (3,280 in males and 2,650 in females).
- About 1,500 deaths from ALL (850 in males and 650 in females).