What Is Chronic Leukemia?
Leukemia is cancer that starts in blood-forming tissue and causes large numbers of blood cells to be produced and enter the bloodstream. Each year, about 29,000 adults and 2,000 children in the United States are diagnosed with leukemia. Leukemia is either chronic (gets worse slowly) or acute (gets worse quickly). In early stages of chronic leukemia, the abnormal blood cells can still do their work, and people with chronic leukemia may not have any symptoms of the cancer. However, as the cancer slowly progresses,
symptoms of chronic leukemia will appear as the number of
leukemia cells in the blood rises.
Understanding Normal Blood Cells
Blood cells form in the bone marrow.
Bone marrow is the soft material in the center of most bones. Immature blood cells are called stem cells and blasts. Most blood cells mature in the bone marrow and then move into the blood vessels. Blood flowing through the blood vessels and heart is called the peripheral blood.
In people with chronic leukemia, the bone marrow produces abnormal white blood cells, which are leukemia cells. At first, leukemia cells function almost normally. However, in time, they may crowd out normal white blood cells, red blood cells, and platelets, which makes it hard for blood to do its work. This may result in infection, anemia, and easy bleeding.
Types of Chronic Leukemia
The type of white blood cell that is affected will determine the type of chronic
leukemia. Chronic leukemia can develop in lymphoid cells or myeloid cells. Chronic leukemia that affects lymphoid cells is called
chronic lymphocytic leukemia (
CLL). Chronic leukemia that affects myeloid cells is called chronic myeloid leukemia (
CML).
Chronic lymphocytic leukemia accounts for about 7,000 new cases of leukemia each year. In most cases, people who are diagnosed with this type of chronic leukemia are more than 55 years of age. CLL almost never affects children.
Other names for chronic lymphocytic leukemia include:
- CLL
- Chronic lymphoblastic leukemia
- Chronic lymphatic leukemia.
Chronic myeloid leukemia accounts for about 4,400 new cases of leukemia each year. This type of chronic leukemia affects mainly adults.
Other names for chronic myeloid leukemia include:
Most people with chronic myelogenous leukemia have a gene mutation (change) called the Philadelphia chromosome.
Every cell in the body contains DNA (genetic material) that determines how the cell looks and acts. DNA is contained inside chromosomes. In CML, part of the DNA from one chromosome moves to another chromosome, this change is called the "Philadelphia chromosome." This will result in the bone marrow making an enzyme, called
tyrosine kinase, which causes too many stem cells to develop into white blood cells (granulocytes or blasts). The Philadelphia chromosome is not passed from parent to child.
No one knows the exact
causes of chronic lymphocytic leukemia, and doctors can seldom explain why one person will get CLL and another person will not. However, chronic
leukemia research has shown that people with certain risk factors are more likely than others to develop this type of chronic leukemia. A risk factor is anything that increases a person's chances of developing a disease.
- Being middle-aged or older, male, or Caucasian
- A family history of chronic lymphocytic leukemia or cancer of the lymph system
- Having relatives who are Russian Jews or Eastern European Jews.
Symptoms of Chronic Leukemia
Like all blood cells,
leukemia cells travel through the body. Depending on the number of abnormal cells and where these cells collect, patients with chronic
leukemia may have a number of chronic
leukemia symptoms.
Tests that examine the blood, bone marrow, and lymph nodes are used to detect and diagnose chronic leukemia.
Tests and procedures that may be used to diagnose chronic leukemia include:
- Physical exam and history
- Complete blood count
- Cytogenetic analysis
- Immunophenotyping
- Bone marrow aspiration and biopsy.
Physical Exam and History
A physical exam entails an exam of the body to check general signs of health, including checking for signs of disease, such as lumps or anything else that seems unusual. A history of the patient's health habits and past illnesses and treatments will also be taken.
Complete Blood Count (CBC)
A complete blood count is a procedure in which a sample of blood is drawn and checked for:
- The number of red blood cells, white blood cells, and platelets
- The amount of hemoglobin (the protein that carries oxygen) in the red blood cells
- The portion of the blood sample made up of red blood cells.
Cytogenetic Analysis
A cytogenetic analysis is a test in which cells in a sample of blood or bone marrow are viewed under a microscope to look for changes in the structure or number of chromosomes in the lymphocytes.
Immunophenotyping
Immunophenotyping is a test in which the cells in a sample of blood or bone marrow are examined under a microscope to find out if malignant lymphocytes (cancer) originated from the B lymphocytes or the T lymphocytes.
Bone Marrow Aspiration and Biopsy
A bone marrow aspiration and biopsy involves the removal of a small piece of bone and bone marrow by inserting a needle into the hipbone or breastbone. A pathologist will then view both the bone and bone marrow samples under a microscope to look for abnormal cells.
- The chronic leukemia stage
- Red blood cell, white blood cell, and platelet blood counts
- Whether there are chronic leukemia symptoms, such as fever, chills, or weight loss
- Whether the liver, spleen, or lymph nodes are larger than normal
- The response to initial chronic leukemia treatment
- Whether the chronic leukemia has recurred (come back).
Choosing the most appropriate treatment for chronic leukemia is a decision that ideally involves the patient, the family, and the healthcare team.
You can learn more about the specific treatments and prognosis for chronic leukemia by going to the eMedTV article
Chronic Leukemia Treatment or learn about each type of chronic leukemia treatment by going to:
