Commonly Used Terms in an AML Diagnosis
Blast cells are immature cells found in bone marrow. They are not fully developed, and therefore, do not yet carry out any particular function within the body. In normal humans, up to five percent of the cells found in bone marrow are blast cells. Normally, blast cells continue to mature within the bone marrow and then begin to carry out set functions. White blood cells make up the immune system. Red blood cells carry oxygen throughout the body and release carbon dioxide to be exhaled by the lungs.
When a higher than normal ratio of blast cells are found within the bone marrow a problem may exist. Leukemia usually occurs when too many white blood cells remain as blast cells. Unlike normal cells, these mutated blast cells do not eventually mature and begin functioning within the body. They usually continue to be immature, and more are often formed at a rapid pace. This eventually causes a low blood count of normal cells. Very high blast counts often require cancer therapies like chemotherapy and radiation to kill off the quickly invading cells. A great reference for the definition of Blast Cells can be found on Ask Kids.
Bone marrow biopsy
A bone marrow biopsy is especially important for accurate diagnosis of AML because AML is defined by greater than 30% blasts in the bone marrow, whereas a normal blast count is less than 5%. In a bone marrow biopsy a sample of bone marrow is taken from the hip bone or another large bone. A bone marrow biopsy measures the blast count.
In order to take a sample of bone marrow a health care provider will clean the skin and apply a local anesthesia to the area and surface of the bone. The next step is removing a liquid sample of marrow by aspiration. A special needle is inserted into the bone. The needle has a tube attached to it that creates the suction. During the biopsy, a cylindrical piece of bone and marrow is removed by suctioning the fluid through the tube. During the aspiration you may feel pressure and then a sharp sucking sensation as the marrow is removed. This only lasts a few moments and then the needle will be removed.
The samples from the bone marrow biopsy are then sent to the laboratory for examination. It's common to have this procedure multiple times during the treatment phase to determine if your leukemia is responding to treatment.
Chemotherapy is the name used by health care providers to describe the use of drugs to kill cancer cells. For a patient diagnosed with AML it is usually the treatment of choice and is used to relieve symptoms and achieve long-term remission of the disease. For AML a combination chemotherapy is used, in simple terms this just means that multiple drugs are used. Generally combination chemotherapy is more effective than using a single drug for the treatment. In chemotherapy not all drugs are administered intravenously through a vein in the arm, some drugs may be given by mouth in the form of pills. When the cancer cells have entered the brain chemotherapy drugs may be put into the fluid that surrounds the brain and spinal cord.
Because the drugs kill healthy white cells as well as cancerous ones, a patient will become extremely vulnerable to bacterial and fungal infections as the immune system is weakened.
Complete Remission (CR)
The disappearance of all signs of cancer in response to treatment. This does not always mean the cancer has been cured. Also called complete response. The goal of AML treatment is to achieve complete remission (CR). In complete remission typically the body has regained its ability to produce blood cells normally and the number of blood cells should return to normal ranges and no leukemic blast cells are detectable in the blood or the marrow.
In the consolidation phase the goal is to reactivate your immune system. The type of postremission therapy used largely depends on the type of AML. Further chemotherapy may be used or bone marrow transplantation if chemotherapy is found to be ineffective. For children chemotherapy to the central nervous system is given. CNS includes the brain and spinal cord. This therapy is important because without it there is a one in five chance of a relapse.
Cytogenetic tests should be performed to determine the number and shape of chromosomes in the DNA of individual blast cells. Cytogenetic tests analyze parts of the nucleus of blast cells. Along with immunophenotyping of cells of the bone marrow, a procedure that involves placing various sorts of stains on bone marrow cells to help identify the chemicals located on the cell surfaces.
A FLT3 Mutation is a genetic mutation sometimes referred to as a chromosomal abnormality in an individual. This genetic mutation may be screened during cytogenetic testing when diagnosed with AML. When your doctor screens for the FLT3 Mutation more accurate prognostic indicators can assist wtih treatment decisions for all AML patients. See FLT3 and AML.
A process used to identify cells, based on the types of antigens or markers on the surface of the cell. This process is used to diagnose specific types of leukemia and lymphoma by comparing the cancer cells to normal cells of the immune system.
Induction therapy is performed at the onset of an AML diagnosis. The goal of this treatment is to stop leukemic cells from multiplying and to drastically lower the percentage of existing ones through 'rapid cell kill'. To plan treatment, doctors look at a patient's risk factors (also called prognostic factors). Risk factors are patient and disease traits that clinical studies have linked to better or worse outcomes from treatment. Examples of risk factors can include a patient's age and subtype of AML. Children with AML will also receive induction therapy.
A type of immune cell. Most leukocytes are made in the bone marrow and are found in the blood and lymph tissue. Leukocytes help the body fight infections and other diseases. Granulocytes, monocytes, and lymphocytes are leukocytes. Also called WBC and white blood cell.
Maintenance usually lasts from one to three years. During this time an AML patient will be monitored closely. It's quite possible to receive chemotherapy and transfusions during the maintenance period. Your hair will start growing back, side effects will begin to subside and a child can return to school. If a relapse occurs, consolidation therapy may begin again and some form of transplant used. Treatment is usually stopped after two years, and if relapse occurs, the disease is allowed to take its course.