New and more effective ways of treating leukemia are being discovered annually. Many people with the disease can live for many fruitful years and be cured.
Doctors design a treatment plan to fit each individual's needs. They consider the type of leukemia, how far it has spread, and whether the person has had other cancer before. The person's age, symptoms, and general health are other factors of consideration.
Although acute leukemias show a more aggressive course, they are more often curable than chronic leukemias. The treatment of acute leukemia attempts to kill leukemia cells so they never grow back. Most doctors say that a person is cured if he or she shows no symptoms for five years after treatment. Chronic leukemias are less often curable. The treatment of chronic leukemia attempts to delay the leukemia from getting worse and to manage symptoms.
Treatment of acute leukemia usually involves three stages: 1) induction for remission, 2) post remission, and 3) therapy at the time of relapse. In addition, preventive therapy for leukemia in the brain is given to persons with ALL.
The standard treatments for adult leukemia are chemotherapy and bone marrow transplantation. Radiation and immunotherapy are used in specific types of leukemia. Since the leukemia cells spread throughout the body, surgery cannot cure this disease. However, surgery is done in some cases of lymphocytic leukemia. For example, if the spleen is swollen a doctor may take out the spleen.
Radiation uses X-rays or other high-energy rays to destroy leukemic cells. It is administered either to the whole body or to only one area. Radiation is used for leukemia in the central nervous system (which includes the brain and spinal cord and in the testicles). It is also used for pain caused by spinal cord compression or expansion of bone marrow as a result of the leukemic cells crowding the bone marrow.
Immunotherapy tries to get the body to fight leukemia. It uses protein made by the body or created in a laboratory to boost, direct, or restore the body's defenses against disease. Use of Interferon-alpha helps to strengthen the immune system and may delay the progression of the CML.
Chemotherapy is the most common way to treat leukemia. Chemotherapy means drug therapy in which various drugs are used either in combination or as a single agent. Drugs taken by mouth or injected into a vein enter the bloodstream and kill leukemia cells in most part of the body. This is called systemic chemotherapy.
Rapidly multiplying cells often are more sensitive to the effects of chemotherapy. Most anti-leukemic drugs interact with DNA, the genetic material contained in all human cells. This interaction changes the DNA in such a way that the cancer cells are killed or are prevented from producing more cancer cells. Unfortunately, rapidly dividing normal cells in the body are also affected by these drugs, which can cause serious side effects.
|| Therapy for induction of remission. Induction refers to initial chemotherapy given to the person with leukemia to induce or produce a complete remission. Complete remission means there are no signs or symptoms of leukemia, and the number of white blood cells and blood cells in the blood and marrow is normal. The success of treatment depends on factors such as the ability to tolerate intensive treatment, the patient's age, and the type of drug regimen.
In AML, the typical induction regimen consists of a combination of anti-cancer drug cytarabine and either one of the anthracyclines: daunorubicin, mitoxanthrone, or idarubicin. This regimen results in 60 to 80% of persons having complete remission.
One exception is the treatment of patients with acute promyelocytic leukemia (APL), a subtype of AML. In APL, a defect in the retinoic acid receptor prevents the normal growth of promyelocytes (precursors to normal myeloid cells). The all-trans-retinoic acid (Tretinoin), a vitamin A derivative, causes leukemia cells to mature and die. This drug is used in addition to the chemotherapy. Another drug, arsenic trioxide, also is available to treat APL.
In ALL, the most commonly used drugs are vincristine, cytarabine, cyclophosphamide, L-asparaginase, and prednisone.
In CML, drugs like hydroxyurea or interferon have been used. A newly approved oral drug, imatinib mesylate (Gleevec) has been successful in promoting remission among the people enrolled in clinical trials. Its effect on long term survival still needs to be seen.
In CLL, chlorambucil, fludarabine, and cyclophosphamide are commonly used in treatment. Chlorambucil produces a 5-year survival in 48% of people affected. With prolonged use, however, the disease becomes resistant to these drugs and progresses.
|| Post-remission therapy. Once the person with leukemia achieves a complete remission and recovers from the adverse effects of induction therapy, post-remission chemotherapy begins. This therapy tries to kill any remaining leukemia cells. Without further treatment, leukemia will recur in the majority of persons. The same drugs may be administered in a modified schedule or in doses.
In AML, high-dose cytarabine is used in persons less than 55 years old. This results in a long-term disease free survival of 5 years by 15 to 50%.
In ALL, the person continues to receive chemotherapy but in smaller doses. A typical maintenance regimen consists of low-dose oral methotrexate and 6-mercaptopurine. In order to stay in remission it may be continued up to several years.
|| Therapy at the time of relapse. Relapse refers to the return of leukemia cells, which were once absent, in the bone marrow. Response to further chemotherapy following relapse is usually poorer than the initial response after the induction therapy. For patients with an eligible donor, bone marrow transplantation (BMT) is an option and it may improve chances of survival.
||Leukemia in the brain. Certain types of leukemia have a tendency to spread to the nervous system. To prevent or to treat this, doctors may inject a drug into the spinal fluid to destroy any cancer cells. This is known as an intrathecal method of administration. Radiation or high doses of systemic chemotherapy are given at the same time with intrathecal chemotherapy.
Bone marrow transplant (BMT). Bone marrow transplants offer some people with leukemia the best chance for a cure. It is usually performed when the leukemia is in remission but has high risk for relapse ; does not respond fully to the treatment, or relapses after treatment. In order to perform the transplant, higher doses of chemotherapy drugs are given. These high dose drugs effectively destroy the person's leukemia cells. They also kill the normal infection-fighting cells of the bone marrow. To compensate for this destruction, healthy marrow cells are taken from the donor whose tissue type is the same as or almost the same as the person with leukemia. These are infused or transplanted into the person's bloodstream through an intravenous (IV) catheter. It is hoped that the transplanted bone marrow will produce healthy white blood cells on its own.
There are two types of marrow transplants. In the autologous marrow transplantation, the person's own healthy bone marrow that has been saved and "cleansed" of leukemic cells are re-infused to replace marrow that was destroyed. In the allogenic transplantation, marrow from a donor with a match of all six cell-markers, known as human leukocyte antigens (HLA), is used to replace the diseased marrow. The healthy marrow may be obtained from either identical twins (best match), or HLA-matched brother or sister, and more recently, from a person who is not related to the person with leukemia.
Based on most clinical studies, the overall survival rate among the different types of BMT was similar. BMT is successful about 50% of the time when measured two years after the treatment. There was a higher relapse rate in autologous BMT due to the failure of getting rid of all the leukemia cells. However, more persons died in the allogeneic BMT due to the complications.
Complications from treatment
Scientists and physicians are constantly searching for new and better ways to treat leukemia. Their effort focuses either on improving the efficacy of current drug therapy, reducing its side effects, or trying to attack leukemia cells in new ways. Click here to view some research treatments currently under active investigation and available mostly through clinical trials.