Chronic myeloid leukemia

Medical quality assurance by Dr. Albrecht Nonnenmacher, MD at March 9, 2016
StartDiseasesChronic myeloid leukemia

Chronic myeloid leukemia (CML) also called chronic myelogenous leukemia is an uncommon form of cancer that is found in blood cells within the bone marrow. The chronic portion of the name indicates that this form of cancer typically progresses more slowly than other forms of leukemia.

Contents

Definition & Facts

CML can affect any person of any age but is rarely found in children. It is most commonly found in older, male adults. Being exposed to excessive amounts of radiation is another risk factor. There are three different phases that this type of cancer could go through:

  • Chronic - This is the earliest phase and usually responses the best to treatment.
  • Accelerated - This is the phase when the cancer will become more aggressive.
  • Blastic - This phase is when the cancer becomes severe and aggressive making it life-threatening.

Symptoms & Complaints

There are a number of symptoms that could point to chronic myeloid leukemia including:

In the earliest phase of chronic myeloid leukemia, there are often no symptoms or signs. The person will not even be aware that the cancer has started. There is a possibility that they could live with chronic myeloid leukemia for months or even years without knowing it.

Causes

Chronic myeloid leukemia is caused when something goes wrong with the genes of a person's blood cells. The issue with the gene begins with a chromosome abnormality. A section of two different chromosomes basically switch places, making one unusually short and one unusually long. The unusually short chromosome is called the Philadelphia chromosome because of where medical researchers originally discovered it. Ninety percent of people that are diagnosed with chronic myeloid leukemia have the Philadelphia chromosome in their blood cells.

The Philadelphia chromosome will then create a new gene - an oncogene within the blood cell, which will then produce an amount of BCR-ABL protein that is abnormal. The protein is what causes cancer to grow because it allows a certain type of blood cell to grow even when it should not.

The normal process of creating red blood cells, white blood cells, and platelets begins in blood cells that are created in the inside of your bones, called bone marrow. The production of immature cells will grow in a controlled number. These cells will then grow and mature into the red and white blood cells and platelets that your body needs.

When a person has chronic myeloid leukemia, this process does not work as it should. The excessive protein causes more white blood cells to be formed than it should. These white blood cells do not grow and then die like other normal cells do; more will continue to form and they do not die, making it too crowded for the healthy cells. This will eventually damage the bone marrow.

Diagnosis & Tests

There are a few different tests and procedures that may be used in order to determine whether or not a person has chronic myeloid leukemia.

  • A physical examination may be done in order to look for different signs and symptoms.
  • Blood tests may be done to check for abnormalities in the blood cells and possibly check how the organs are functioning.
  • A sample of the bone marrow will be collected to look for abnormalities in the blood cells within it.
  • Other tests may be done that will look at the cells to determine whether or not the Philadelphia chromosome exists.

Treatment & Therapy

The goal in the treatments for chronic myeloid leukemia is to destroy the cells that contain the excessive protein. There are a number of treatments used that include:

  • Drugs that will target and destroy the cells containing the excess protein called tyrosine kinase inhibitors. These drugs include imatinib (Gleevec®), omacetaxine (Synribo®), dasatinib (Sprycel®), bosutinib (Bosulif®), and nilotinib (Tasigna®). If the cancer does not respond to the prescribed drug, a different target drug may be prescribed or another treatment may be used.
  • A bone marrow transplant is another treatment that is considered. It is a treatment that carries higher risks with it, so there is a great amount of consideration that is put into whether it is a good treatment for each patient on an individual basis.
  • Chemotherapy drugs are also used to treat chronic myeloid leukemia. These types of drug are specialized in treating cancer and can help to eliminate the cancerous cells.
  • Biological therapy is a way of getting the person's own immune system to fight the cancer cells. Interferon is a biological drug that can help reduce the body's production of cancerous cells.
  • Clinical trials may also be considered in the treatment. There are often new drugs coming out and can be used to fight against cancer and many other diseases, but they may come with risks that are not even known yet.

Prevention & Prophylaxis

Preventing chronic myeloid leukemia is difficult because there are few known risk factors that cause the disease. Avoiding radiation is the best possible way to prevent it.