Acute promyelocytic leukemia, or APL, is a subtype of Acute Myelogenous Leukemia, which is also known as acute myeloid leukemia and AML. The American Cancer Society describes these leukemias as starting in the cells that go on to form white and red blood cells and platelets. APL is an acute leukemia, as compared to a chronic leukemia, which means this type of cancer grows fairly quickly.
Significance
According to St.Jude Children's Research Hospital, out of the 500 children diagnosed with AML each year in the United States, only 50 are diagnosed with APL. This disease makes up 1 percent of leukemias diagnosed in childhood. The majority of diagnoses of APL are in children between the ages 2 and 3, and in adults over 40 years old; but it can be diagnosed at any age.
Types
The American Cancer Society describes eight stages of AML that are classified as M0 to M7. APL is considered M3, which means this cancer consists of blood cells called promyelocytes, which are similar to myeloblasts, cells that eventually grow into blood cells called granulocytes.
Symptoms
Leukemia cells crowd out normal healthy blood cells, causing symptoms of leukemia. Some of these symptoms can include anemia, fatigue, frequent infections, bruising or bleeding easily, loss of appetite, and swollen abdomen, according to the American Cancer Society. Blood tests, bone marrow biopsies, lumbar punctures and lymph node biopsies are all procedures used to help make a diagnosis of leukemia and APL.
Treatment
Although APL is a form of AML, the treatment for this form of leukemia is different than that of AML. Treatment consists of induction, consolidation and maintenance. For induction therapy, in addition to chemotherapy, a drug known as all-trans retinoic acid, also known as ATRA, is given to induce remission. ATRA is a drug that is related to vitamin A, a retinoid. According to Chemocare.com, retinoids help control cell growth and death and are added to treatment for various kinds of cancers. Consolidation therapy is much like induction, with the continuation of chemotherapy and ATRA; and maintenance therapy consists of ATRA and chemotherapy for approximately one year, according to the American Cancer Society.
Prognosis
St.Jude Children's Research Hospital estimates that nearly 75 to 80 percent of patients with APL survive long term when treated with a combination of chemotherapy and ATRA.
