Leukemia

Types of Leukemia and Common Risk Factors

Leukemia is a disease that affects blood-forming cells in the body. It is a cancerous condition characterized by an abundance of abnormal white blood cells in the body. Leukemia begins in the bone marrow and spreads to other parts of the body. Both children and adults can develop leukemia.

Characterizing Different Types of Leukemia

Leukemia can be divided into four different types. It is first classified as acute or chronic, and then classified as either being myelogenous or lymphocytic.

Acute vs Chronic Leukemia

In chronic leukemia, the leukemia cells come from mature, abnormal cells. These cancers are usually slower growing than the acute leukemias.

Acute leukemias, on the other hand, develop from early, immature cells, called "blasts."  Thesee young cells divide rapidly and these cancers usually grow more rapidly than the chronic leukemias.

Myelogenous vs Lymphocytic

Leukemias are also distingushed by the type of cell line they derive from.

Myelogenous leukemia develops from myeloid cells. The disease can either be chronic or acute, referred to as chronic myelogenous leukemia (CML) and acute myelogenous leukemia (CML). There are several types of myelogenous leukemia.

Lymphocytic Leukemia
Lymphocytic leukemia develops from cells in the lymphoid cell line in the blood marrow. The disease can be acute or chronic, referred to as chronic lymphocytic leukemia (CLL) and acute lymphocytic leukemia (AML).

There are several types of lymphocytic leukemia as well.

Types of Leukemia

If you are looking for information on a specific type of leukemia,

Causes and Risk Factors of Leukemia

While we don't know exactly what causes leukemia, researchers have identified several risk factors.

  Some of these are risk factors for specific cancers, for example the chronic leukemias are mroe common in older adults, whereas acute lymphocytic leukemia is more common in children.  Those at risk for leukemia may include:

  • People older than the age of 60, but it can occur in younger people
  • People who smoke (at least with acute myelogenous leukemia)
  • People who have undergone previous chemotherapy or radiation therapy
  • People infected with the human T-cell leukemia virus, a virus that infects T-cells that is spread by sharing syringes and used to inject drugs; through blood transfusions; through sexual contact; and from mother to child at birth or through breastfeeding
  • People with myelodysplasctic syndrome, a blood disorder
  • People with Down syndrome
  • People with a family history of leukemias and lymphomas

Symptoms of Leukemia

Leukemia symptoms can occur all of a sudden or gradually. The symptoms are broad, but there are specific signs of leukemia to keep an eye out for:

  • Fever
  • Recurrent infections
  • Excessive bruising
  • Fatigue
  • Physical exercise intolerance
  • Abdominal pain, or generally feeling fullness
  • Unintentional weight loss
  • Abnormal bleeding
  • Enlargement of the lymph nodes spleen and/or liver
  • Weakness

Diagnosing Leukemia

A doctor may suspect you have leukemia after completing a physical or if you report experiencing the symptoms of leukemia. There are instances when leukemia is suspected from results of blood tests performed for other reasons. There are several tests a doctor may use to diagnose leukemia, ranging from blood tests to spinal taps.

Physical Exam. During a physical exam, a doctor may look for lumps, swollen lymph nodes and other abnormalities or symptoms of leukemia. A thorough medical history will be taken and the patient can report a history of leukemia or any symptoms or risk factors.

Blood Tests. Blood tests, such as complete blood count (CBC) can detect leukemia. A CBC determines the number of red blood cells, white blood cells and platelets.

  • Peripheral blood smear - determines the presence of blast cells and reveals the type and quantity of white blood cells
  • Cytogenic analysis - is a blood test in which a sample of blood is examined to check for changes in the chromosomes of the lymphocytes
  • Other various blood tests - other blood tests may be ordered to see how organs are functioning and if they are being affected by leukemia

Biopsy. A biopsy is a procedure in which a sample of cells are removed from the body to be examined for cancer. Bone marrow biopsy is used to diagnose leukemia. A large bore needle is inserted in to the hip or, rarely, the breast bone and a sample of the bone is removed and bone marrow is then aspirated. The material is then examined by a pathologist. A lymph node biopsy may also be performed depending on the type of leukemia suspected.

Lumbar Puncture/Spinal Tap. A lumbar puncture or spinal tap may be done to diagnose leukemia. Under a local anesthetic, a small amount of spinal fluid is removed from the spaces between the vertebrae in the spine. The fluid is then examined by a pathologist.

Leukemia Treatment

Treatment for leukemia varies greatly depending on the type of leukemia and stage of the disease. Treatments often include a combination of methods.

Chemotherapy. Chemotherapy is the use of drugs that either kill cancer cells or prevent the cells from dividing. Chemotherapy can be given in a variety of ways, with IV infusion and pill being more common. The type of chemotherapy given depends on the stage and type of cancer.

Radiation Therapy. Radiation therapy is the use of certain types of energy to kill cancer cells and shrink tumors. This energy can be waves or particles like protons, electrons, x-rays and gamma rays.

Biologic Therapy. Biologic therapy is treatment that uses the knowledge specific to the cancer to eliminate it. Substances made by the body or made in a laboratory are used to boost, direct or restore the body's natural defenses against cancer or to specifically shut down its division.

Surgery. Surgical removal of the spleen is also a treatment option for chronic leukemia. The spleen collects leukemia cells, and they accumulate, causing the spleen to enlarge. An enlarged spleen can cause many complications.

Peripheral blood stem cell transplant or bone marrow transplant.  A stem cell transplant is a procedure to replace normal marrow production that has been destroyed by treatment with high doses of anticancer drugs or radiation. Transplantation may be autologous (an individual's own stem cells saved before treatment), allogeneic (stem cells donated by someone else) or syngeneic (stem cells donated by an identical twin).

Sources:

National Cancer Institute. Leukemia – Health Professional Version (PDQ). Accessed 04/17/16. http://www.cancer.gov/types/leukemia/hp

Leukemia Prevention

Unfortunately, there are no proven leukemia prevention methods. Even more sadly, most of the risk factors cannot be avoided like in other types of cancer. We simply cannot avoid aging or having conditions like Down's Syndrome. There are some risk factors we can avoid that may aid in leukemia risk reduction, like not smoking. If you smoke cigarettes, now is the time to quit. Smoking puts you at risk for many types of cancer, including acute myelogenous leukemia. 1 in every 4 cases of AML is linked to smoking.

Reducing your exposure to benzene may reduce your risk of developing leukemia. Benzene is a chemical by product of coal and petroleum, used mainly is gasoline. It is also contained in other things such as paints, solvents, plastics, pesticides and detergents. People who work in the manufacturing of these products may be putting themselves at risk for leukemia.

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