Signs and Symptoms of Chronic Leukemia
At least one-fifth of people with chronic leukemia have no symptoms at the time their cancer is diagnosed. Their cancer is diagnosed by blood tests performed during an evaluation some unrelated health problem or during a routine checkup. Even when symptoms are present, they are often vague and nonspecific. Most symptoms of chronic leukemia, such as weakness, fatigue, reduced exercise tolerance, weight loss, fever, bone pain, and pain or a sense of "fullness" in the abdomen (especially after eating a small meal) can also occur with other cancers as well as many noncancerous conditions.
Many of the signs and symptoms of chronic leukemia occur because the leukemic cells replace the bone marrow's normal blood-producing cells. As a result, people do not have enough properly functioning red blood cells, white blood cells, and blood platelets.
Anemia, a shortage of red blood cells, causes excessive tiredness, a "pale" color to the skin, and in more serious cases, shortness of breath.
Not having enough normal white blood cells (called leukopenia) and, in particular, too few mature granuloctyes (called neutropenia or granulocytopenia) increases the risk of infections. The most common term you may hear is neutropenia, which refers specifically to low neutrophils (a type of granulocyte). Although leukemia is a cancer of white blood cells and patients with leukemia may have very high white blood cell counts, the leukemic cells do not protect against infection the way normal white blood cells do.
Thrombocytopenia (not having enough of the blood platelets needed for plugging holes in damaged blood vessels) can lead to excessive bruising, bleeding, frequent or severe nosebleeds, and bleeding gums. Thrombocytosis means that the blood platelet count is too high. Some patients with CML have thrombocytosis, but their platelets may not function properly, sometimes leading to bleeding and bruising problems.
Leukemia cells may spread to the brain and spinal cord, the testicles, ovaries, kidneys, and other organs. Involvement of some organs may not cause any symptoms. Spread to the brain may cause headaches, weakness, seizures, vomiting, difficulty in maintaining balance, or blurred vision.
Some patients have bone pain or joint pain caused by leukemic cells spreading from the marrow cavity to the surface of the bone or into the joint.
Leukemia often causes enlargement of the liver and spleen, organs located on the upper right and upper left side of the abdomen, respectively. Enlargement of these organs may be noticed as a fullness, or even swelling, of the belly. These organs are usually covered by the lower ribs but when they are abnormally large, they can be felt by the doctor.
Leukemia may spread to lymph nodes. If the affected nodes are close to the surface of the body (for example, lymph nodes on the sides of the neck, in the groin, the underarm areas, and above the collarbone), the patient or health care provider may notice the swelling. Swelling of lymph nodes inside the chest or abdomen may also occur, but can be detected only by imaging tests such as computed tomography (CT) or magnetic resonance imaging (MRI) scans. Lymph node swelling often occurs with CLL, but is rare among patients with CML or HCL.
Types of Specimens Used in Diagnosis and Evaluation of Leukemia
If signs and symptoms suggest a person may have leukemia, the doctor will need to check samples of blood and bone marrow in order to be certain of this diagnosis. Other tissue and cell samples may also be taken in order to guide treatment.
Blood cell counts and blood cell examination: These tests recognize changes in the numbers of different blood cell types and in the appearance of these cells under the microscope. Most patients with chronic leukemia have too many white cells in their blood, not enough red blood cells, and not enough blood platelets. Even though these findings suggest leukemia, usually the disease cannot be accurately diagnosed without testing a sample of bone marrow cells.
Blood chemistry tests: These tests measure the amount of certain chemicals in their blood but are not used to diagnose leukemia. In patients already known to have leukemia, these tests help detect liver or kidney problems due to damage caused by the spread of leukemic cells or to the side effects of certain chemotherapy drugs.
These tests also help determine whether treatment is needed to correct abnormally low or high blood levels of certain minerals.
Bone marrow tests: The bone marrow sample is taken from the pelvis. The patient lies on the stomach and the doctor feels the bones at the top of the buttocks. The area is cleaned with a special soap. Prior to the bone marrow test, your doctor will inject a local anesthetic, usually lidocaine, into the back of the pelvic bone about an inch or two from the middle of your back. This will cause some very brief stinging. When this has had a few moments to take effect, the doctor will make a small cut so he or she can insert a needle (the needle is about half as wide as a pencil and has a handle on one end that the doctor holds while he or she moves it through your bone). The biopsy needle is moved through the bone with a twisting motion. In bone marrow aspiration, a syringe is used to suck out a small amount of liquid bone marrow (about 1 teaspoon). Sometimes the needle going into the bone is painful, but it only lasts a short time. The sucking out is often painful or at least uncomfortable for a brief moment.
Usually this is followed by a bone marrow biopsy in the same area. The doctor will carefully move the needle further into the bone marrow to collect a second sample of bone marrow called a core biopsy. This contains a small solid piece of bone and marrow (about 1/16 inch in diameter and ½ inch long) is removed with a slightly larger needle. You may also feel some pressure as the doctor removes the marrow specimen. After the needle is pulled out, this solid sample is pushed out with a wire so that it can be examined under a microscope. You will have pressure held against your buttock at the biopsy site for a few minutes and a pressure dressing applied. These bone marrow tests are used to diagnosis leukemia and later, to tell if the leukemia is responding to therapy.
Excisional lymph node biopsy: A surgeon cuts through the skin to remove the entire lymph node. If the node is near the skin surface, this is a simple operation that can be done with local anesthesia (numbing medication), but if the node is inside the chest or abdomen, general anesthesia (the patient is asleep) is used. This procedure is important in diagnosing lymphomas, but is only rarely used to diagnose chronic lymphocytic leukemia.
Lumbar puncture: A doctor places a small needle into the spinal cavity in the lower back (below the level of the spinal cord) to withdraw some cerebrospinal fluid (CSF), to look for leukemia cells. This procedure is not a routine test for patients with chronic leukemia and is only done if the patient is suspected of having leukemia cells in their brain and or spinal cord.
Laboratory Tests Used to Diagnose and Classify Leukemia
Routine microscopic exam: All of the samples (bone marrow, lymph node tissue, blood and cerebrospinal fluid) are examined under a microscope. The samples are usually examined by a pathologist (doctor specializing in diagnosis of disease by laboratory tests) and are often reviewed by the patient's hematologist/oncologist (doctor specializing in medical treatment of blood diseases and cancer). The doctors will look at the size and shape of the cells and whether they contain granules (microscopic collections of enzymes and other chemicals that help some types of white blood cells fight infections).
Based on a cell's size, shape, and granules, doctors can classify bone marrow cells into specific types. An important element of this cell classification is whether the cell appears mature (resembles normal cells of circulating blood, that can fight infections and are no longer able to reproduce) or immature (lacks features of normal circulating blood cells, not effective in fighting infections, and are able to reproduce). The most immature cells are called blasts.
Another important feature of bone marrow samples is its cellularity. Normal bone marrow contains hematopoietic (blood-forming) cells and fat cells. Marrow with too many blood-forming cells is said to be hypercellular. If too few of these cells are found, the marrow is called hypocellular.
Cytochemistry: After cells from the sample are placed on glass microscope slides, they are exposed to chemical stains (dyes) that are attracted or react with to only some types of leukemia cells. These stains cause a color change that can be seen only under a microscope. The leukocyte alkaline phosphatase (LAP) test is particularly useful in distinguishing CML from other types of leukemia and benign blood conditions.
Flow cytometry: This test is sometimes used to examine the cells from bone marrow, lymph nodes and blood samples. It is very accurate in determining the exact type of leukemia. A sample of cells is treated with special antibodies and passed in front of a laser beam. Each antibody sticks only to certain types of leukemia cells. If the sample contains those cells, the laser will cause them to give off light that is measured and analyzed by a computer. This test is often helpful with classification of acute leukemias but is not needed for most chronic leukemia patients.
Immunocytochemistry: As in flow cytometry, cells from the bone marrow aspiration or biopsy sample are treated with special antibodies. But instead of using a laser and computer, the sample is treated so that certain types of cells change color. The color change can be seen only under a microscope. Like flow cytometry, it is sometimes helpful in determining the exact type of an acute leukemia, but is not necessary in most cases of chronic leukemia.
Cytogenetics: Normal human cells contain 46 chromosomes, pieces of DNA and protein that control cell growth and metabolism. In certain types of leukemia, part of one chromosome may be attached to part of a different chromosome. This change, called a translocation, can usually be seen under a microscope. Recognizing these translocations helps in identifying certain types of CLL and CML and is important in determining the patient's prognosis (the outlook for chances of survival) and in choosing the most suitable treatment.
Over 90% of CML patients have a translocation between chromosomes 9 and 22 present in their leukemic cells. This chromosome change is called the Philadelphia chromosome and was named by the doctors from that city who first noticed the translocation. This was the first translocation discovered that is consistently found in a specific type of cancer. This translocation is not only a useful feature in helping to identify this type of cancer, it has an important role in making the cells cancerous, and studies of the regions of DNA affected by the translocation have provided much information about genes that cause cancer.
Some types of leukemia have an abnormal number of chromosomes. For example, cells in 10 to 20 percent of patients with CLL have three copies of chromosome 12, instead of the usual two copies and about 25 percent have a deletion in chromosome 13.
Cytogenetic testing looks at chromosomal abnormalities. The testing usually takes around 3 weeks, because the leukemic cells must grow in laboratory dishes for a couple of weeks before their chromosomes are ready to be viewed under the microscope. The results of cytogenetic testing are written in a shorthand form that describes which chromosome changes are present.
- A translocation, written as t(9:22), for example, means a part of chromosome 9 is now located on chromosome 22, and part of chromosome 22 is now attached to chromosome 9.
- An inversion, written as inv 16 for example, means that part of the chromosome 16 is upside down and is now in reverse order but is still attached to the chromosome it originated from.
- A deletion, written as -7, for example indicates part of chromosome 7 has been lost.
- An addition, +8 for example, happens when all or part of a chromosome has been duplicated, and too many copies of it are found within the cell.
Molecular genetic studies: Certain substances, called antigen receptors, occur on the surface of lymphocytes. Normal lymphoid tissue contains cells with many different antigen receptors, which help the body respond to infection. Lymphocytic leukemias (such as CLL), however, start from a single abnormal lymphocyte, so all leukemic cells in a patient have the same antigen receptor. Laboratory tests of the DNA that contains information on each cell's antigen receptors are a very sensitive way to diagnose CLL. Because different subtypes of CLL cells have different antigen receptor features, this test is sometimes helpful in CLL classification. However, the test is not necessary in most cases.
DNA tests of leukemia cells can find most translocations that can be seen under a microscope in cytogenetic tests. DNA tests can also find some translocations involving parts of chromosomes too small to be seen with usual cytogenetic testing under a microscope. This sophisticated testing is not needed in most cases of chronic leukemia, but it is sometimes helpful in classifying CML. Between 5% and 10% of CML cases do not have the Philadelphia chromosome on cytogenetic testing. In over half of these Philadelphia chromosome-negative cases, the translocation involving chromosomes 9 and 22 can be identified by a DNA test called polymerase chain reaction (PCR). Information about these translocations may be useful in predicting response to treatment. These tests are also useful after treatment in finding small numbers of remaining leukemia cells that may be missed under a microscope. See the section "What's New In Chronic Leukemia Research and Treatment?" for information on recent advances in genetics of chronic leukemia.
Imaging studies are ways of producing pictures of the inside of the body. There are several imaging studies that might be done in people with leukemia.
X-rays: During the course of diagnosis and evaluation of a person with leukemia, a chest x-ray and a bone scan are often obtained. These may show a mass in the chest, or evidence of leukemia in the bones or rarely in the joints.
Computed tomography (CT) scan: This is a special kind of x-ray in which the beam moves around the body, taking images from different angles. The images are then combined by a computer to produce a detailed cross-sectional picture of the inside of the body. CT scans are not often used in leukemia, but they can show involvement of lymph nodes in the chest or in the back of the abdomen. Involvement of these areas can occur in CLL.
Magnetic resonance imaging (MRI): This procedure uses powerful magnets and radio waves to produce computer-generated pictures of internal organs. The pictures look very similar to a CT scan, but are more detailed. This scan may be used when there is concern about leukemia involving the brain.
Ultrasound: This test uses sound waves to produce images of internal organs. The test can distinguish solid from fluid-filled masses. It can help to show whether the kidneys, liver, or spleen have been affected by leukemia.