Acute Promyelocytic Leukemia

Acute Promyelocytic Leukemia General Information

Acute Promyelocytic Leukemia, a rare blood cancer is a type of AML (acute myelogenous leukemia) meaning a subtype of bone’s blood and marrow malignancy and it is provoked by APL. Some specialists call it acute progranulocytic leukemia, APL, PML-RARA, or AML with (t15:t17) (q22:q12). This disorder consists in an unusual accumulation of granulocytes that are not yet completely mature, named promyelocytes and a decreased number of mature blood cells that are found in the cell’s myeloid line. The main characteristic of Acute Promyelocytic Leukemia is the translocations of the chromosomes that involve in the process the RARA gene (retinoic acid receptor or RARα), the chromosomes 15 and 17. This action produces a protein that is chimeric and does not allow the complete growing up of the myeloid cells, stopping them at the stage of promyelocytic by reducing the differentiation of the terminal cells. These cells block the healthy, normal cells of the blood as a result of the fact that they can not carry the normal function that belong to them. This form of AML is different from the all others because of the responsiveness to all therapies with ATRA (trans retinoic acid). Acute Promyelocytic Leukemia affects 10% of the adults around the age of 50, while the other types of AML appear in persons over 65 years old. If a patient has AML the chances of getting APL are very high so that they must be carefully treated. It was also discovered that the most predisposed people for this disorder are the Latin Americans.

Acute Promyelocytic Leukemia Symptoms

Acute Promyelocytic Leukemia is very aggressive, being a fast growing, deathly and serious form of leukemia. The symptoms are not very different from other types of leukemia having similar manifestations with the others. The symptoms may differ from patient to patient due to the fact that every person has a unique body and the resistance of it to various diseases is not known. Usually the symptoms are provoked by the lack of white and red blood cells. Once the promyelocytes have accumulated in the bone marrow, the production of normal healthy platelets and red blood cells lowers and the main health status of the patient are characterized by general anemia and severe thrombocytopenia. In the peripheral blood the specialists can observe the existence of low white cell count (leucopenia) and a high white cell count (leukocytosis). The anemia usually leads to other numerous symptoms: tiredness, weakness, shortness of breathing with exertion or loss of appetite. The coagulopathy and the thrombocytopenia provoke bleeding or easy bruising and the low number of normal white cells of the blood manifests as frequent and persistent infections and intense fever. In many cases, these symptoms are accompanied by joint and bone pain, weight loss and pin-head sized flat marks that are found under the skin and are caused by bleeding, known as petechiae. Some doctors believe that the bleeding may be a cause of DIC (disseminated intravascular coagulation) with which they often associate Acute Promyelocytic Leukemia. In the past years researchers made progresses in understanding the causes of this type of leukemia.

Acute Promyelocytic Leukemia Treatment

To treat any form of leukemia is important to understand the changes in the DNA that determine the normal cells from the bone marrow to transform into leukemia cells. When you present various symptoms that suggest you have leukemia, the doctor will demand tests of the blood cells with the help of a complete blood cell count. In the cases that the results are not as they should be and the results are abnormal, your health care provider will require a bone marrow biopsy.  The testing of Acute Promyelocytic Leukemia is made on reverse transcriptase-polymerase chain reaction or more easily, RT-PCR. This is a test that helps determining the adequate therapy and the status of the disease. If it is positive, the patient can receive chemotherapy earlier. Acute Promyelocytic Leukemia is believed to be a curable subtype of AML, may be the most curable of all. A standard therapy is based on a combination of anthracycline (used in chemo as antibiotic) and ATRA (all-trans retinoic acid), a form of vitamin A (non-chemotherapy drug that targets the leukemia cells). Acute Promyelocytic Leukemia is believed to be the most sensitive form of cancer to ATRA. This therapy is associated with the unique adverse effect of retinoic acid syndrome (fever, dyspnea, peripheral edema, weight gain), treated with dexamethasone. If a patient is diagnosed on time and the therapy is applied properly, more than 75% of the cases achieve long-time remission, being more than probably cured.

Although this treatment has been improved by the researchers, the last 15% of the patients resist to this therapy with ATRA and often relapse. Another method was the one that used high doses of chemotherapy. But this one proved to be toxic for some people and not always lead to cure. In younger relapse patients, a low percentage may be helped with bone marrow transplantation in order to achieve the cure. In some clinics the arsenic trioxide was studied as an additional therapy for relapsed patients or did not respond to the treatment. For them, this become a standard care because it transforms the mature leukemia cells into white cells, kills the cancerous cells and stops them from developing inside the body. In many forms of cancer the main therapy is the one using drugs (chemotherapy) in order to stop the cancerous cell from growing and killing the cells before they divide stopping their process. A first drug used against Acute Promyelocytic Leukemia is the anthracycline that disrupts the DNA structure and finishes its actions. From this family of drugs, the most used are idarubicin and daunorubicin that have successful results in more than 50% of the cases. In combination with anthracycline may also be used an antimetabolite, cytarabine that interferes in the cell growth being used in many more forms of cancer. All patients diagnosed with Acute Promyelocytic Leukemia must follow at least three of these therapies that depend on the phase of the treatment. The phases of any treatment are: Induction therapy, Consolidation therapy and maintenance therapy and every patient should benefit of this program