Acute Leukemia Treatment Strategies

With prompt medical attention, the prognosis for acute leukemia is generally favorable. Treatment is intensive: remission—the absence of cancerous activity—is the first goal, followed by further treatment to prevent a relapse.

Induction is the initial stage of acute leukemia treatment. Chemotherapy and other techniques are used to achieve remission. Once remission occurs, consolidation of the disease begins. Consolidation aims to prevent a relapse over the first two to six months of remission, and usually employs less intensive treatment than induction.

If consolidation is successful, treatment moves into the maintenance phase, which uses even milder therapy than consolidation, and may last for several years to ensure long-term survival.

Chemotherapy is the therapy of choice for most forms of acute leukemia. The powerful drugs halt the production of both abnormal and healthy bone marrow cells. This may result in a number of unwanted side effects, including low levels of platelets (with accompanying bleeding problems), anemia and infection.

The chemotherapy medication used for ALL is different from that used for AML. AML induction responds best to idarubicine or daunorubicine, often combined with cytarabine or mitoxantrone, etoposide or cytarabine. ALL chemotherapy commonly uses glucocorticoids, vinkaalkaloids, anthracyclines, L-asparaginase, and cyclophosphamide.

In some patients, intensive chemotherapy is combined with a bone marrow transplant to increase the chance of successful remission. Healthy stem cells are allogeneic—provided by a donor—or autologous—harvested from the patient's own marrow. Clinical trials are under way to assess the efficacy of stem cells gathered from umbilical cord blood.

A bone marrow transplant is not surgery: the stem cells are delivered to the bloodstream intravenously. Once in the body, they mature into platelets, and white and red blood cells.

 

AML Survival Rates Long term survival rates for AML fall between thirty to fifty percent. A younger person who receives a bone marrow transplant has the best odds of long-term survival, at forty to fifty percent.

Most AML subtypes are treated in the same way. The M3 variant, also called acute promyelocytic leukemia (APL), responds to a specific form of therapy. All-trans retinoic acid (ATRA) allows APL cells to mature into healthy white blood cells. The effect of the medication lasts only a few weeks, however, so the treatment is usually combined with chemotherapy.

AML cells often contain a protein known as CD 33, a protein that is absent from most normal cells. This discovery has prompted the use of novel therapies. For example, gemtuzumab ozogamicin (Mylotarg®), recently approved by the FDA, is an antibody that targets CD 33 proteins and assists the patient's immune system in recognizing and eradicating the malignant cells.

 

ALL Survival Rates Adults with ALL have a thirty to forty percent long-term survival prognosis. Survival rates for adults with ALL drop to ten to twenty percent with negative prognostic factors or if the individual is over sixty years old. Overall survival rates for children with ALL are eighty percent.

ALL has a high rate of remission: between eighty to ninety percent. However, relapses within the first few years are common; only thirty to forty percent of ALL cases remain disease-free five years after remission. A bone marrow transplant may help combat relapse, and may be recommended during the induction or consolidation phase if the patient has a high risk of relapse.

ALL can spread to the central nervous system (CNS). To help prevent this, consolidation may include CNS prophylaxis. Chemotherapy drugs are injected directly into the spinal column to reduce the risk of CNS infiltration.

The aggressive nature of chemotherapy, coupled with leukemia complications, requires careful supportive treatment. Low levels of healthy white blood cells reduce the body's ability to fight infection. Broad-spectrum antibiotics are given intravenously at the first signs of fever, and prophylactic treatment is used to combat fungal, bacterial or viral infections.

Anemia is a common complication. A red blood cell transfusion can help reduce anemia symptoms. Bleeding and blood clotting difficulties may occur due to low levels of platelets. The platelet count is carefully monitored, and transfusions of platelets are given if required.

During leukemia treatment, cells die and are replaced at a rapid rate. This can trigger uric acid stones. Proper hydration is the best preventive treatment. Uric acid stones can also be prevented with allopurinol.

Resources

Beers, M. H., & Berkow, R., (ed). Leukemia. The Merck Manual of Diagnosis and Therapy, 17th Edition. Merck Research Laboratories, NJ, 1999.

Fauci, A., Braunwald, E., Isselbacher, K., Wilson, J., Martin, J., Kasper, D., Hauser, S., & Longo, D. (ed). (1998). Harrison's Principles of Internal Medicine, 14th Edition. McGraw-Hill, NY, 1998.

Leukemia and Lymphoma Society. (updated 2004). Leukemia.

Lewis, C. (2002). Living with leukemia. U.S. Food and Drug Administration.

Smith, M., Ries, L., Gurney, J., & Ross, J. (nd). Leukemia. National Cancer Institute.