Diagnosis

Doctors use many tests to diagnose cancer and determine more about the disease. Some tests may also determine which treatments may be the most effective. For most types of cancer, a biopsy is the only way to make a definitive diagnosis of cancer. If a biopsy is not possible, the doctor may suggest other tests that will help make a diagnosis. Imaging tests may also be used. Your doctor may consider these factors when choosing a diagnostic test:

• Age and medical condition
  
  
• The type of cancer suspected
  
  
• Severity of symptoms
  
  
• Previous test results

The following tests may be used to diagnose or monitor CML:

Blood tests. Many people are diagnosed with CML before they have any symptoms through a blood test, called a complete blood count (CBC), which counts the number of different kinds of cells in the blood. A CBC is often done as part of a regular physical examination. People with CML have high levels of white blood cells. In advanced stages of CML, there may be low levels of red blood cells (anemia) or either elevated or decreased numbers of platelets.

Bone marrow biopsy. In a bone marrow biopsy, a doctor takes a sample of marrow, usually from the back of the hipbone, with a needle. The patient is given medication to numb the area beforehand. The cells from the marrow, along with the cells from the blood, are analyzed by a pathologist (a doctor who specializes in interpreting laboratory tests and evaluating cells, tissues, and organs to diagnose disease). Marrow samples may also undergo cytogenetic analysis (see next).

Cytogenetics. Cytogenetics is the analysis of a cell’s chromosomes, including the number, size, shape, and arrangement of the chromosomes. This test can often be done on the peripheral (circulating) blood at the time of diagnosis. After treatment, though, cytogenetics is performed on the bone marrow sample. All people with CML have the Philadelphia chromosome or the BCR-ABL fusion gene (described in the Overview), so the presence of either is used to confirm the diagnosis. In a small percentage of patients, there are clinical findings that first suggest CML, but the patients do not have the Philadelphia chromosome or the BCR-ABL fusion gene; therefore, they have a different type of chronic myeloproliferative disease (a disease in which there is too many red blood cells, white blood cells, or platelets). Treatment of this disease is different from that of CML.

Cytogenetic testing is also used to monitor how well treatment is working and if it is reducing the number of cells with the Philadelphia chromosome. The following tests are sometimes used in conjunction with cytogenetic testing:

• Fluorescent in situ hybridization (FISH) is a test used to identify the BCR-ABL fusion gene and to monitor patients receiving treatment. This test can be done using a blood sample or bone marrow cells.
  
  
• Polymerase chain reaction (PCR) is a DNA test that can detect the BCR-ABL fusion gene and other molecular abnormalities. Patients receiving treatment may also be monitored with PCR tests. This test is quite sensitive and, depending on the one used, can detect one abnormal cell mixed among approximately 1 million normal cells. This test may also be done using a blood sample or bone marrow cells.

Imaging tests. Doctors may use imaging tests to determine if the cancer is affecting other parts of the body. For example, a computed tomography (CT or CAT) scan or ultrasound examination is sometimes used to assess the size of the spleen in patients with CML. A CT scan creates a three-dimensional picture of the inside of the body with an x-ray machine. Sometimes, a contrast medium (a special dye) is injected into a patient’s vein to provide better detail. An ultrasound uses high-frequency sound waves to produce images of the inside of the body.

Learn more about what to expect when having common tests, procedures, and scans.

Find out more about common terms used during a diagnosis of cancer.

Phases

The clinical course of CML is divided into three different phases: chronic, accelerated, or blastic. This classification helps doctors plan treatment and predict prognosis (chance of recovery).

Chronic phase. The blood and bone marrow contain less than 5% blasts (immature leukemia cells) in samples of blood and bone marrow. This phase often lasts for several years. About 90% of people are in chronic phase at the time of diagnosis.

Accelerated phase. In the accelerated phase, there are more than 5%, but less than 30%, blasts in both the peripheral blood and bone marrow. These cells often have new cytogenetic changes, which develop as the CML cells gain more mutations (DNA damage) and grow faster.

Blastic phase (blast crisis). In the blastic phase, there are more than 30% blasts in the peripheral blood or bone marrow. It develops when the CML cells begin behaving like acute leukemia. Patients in blast crisis often have fever, malaise (feeling unwell), an enlarged spleen, weight loss, and other symptoms.

Without effective treatment, CML in all patients in chronic phase will move into blast crisis approximately five years after diagnosis. The time for the disease to move to blast crisis is generally shorter for patients who have certain specific findings at the time of diagnosis, including higher numbers of blasts or cells called basophils (a special type of white blood cell), chromosome changes in addition to the Philadelphia chromosome, significant elevations of the white blood cell count, or greater enlargement of the spleen.