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There are two primary goals in the treatment of acute myelogenous leukemia (AML):

• The initial goal is to achieve complete remission ("CR"), meaning that there is no evidence of the disease and, as a result of the reduction in the number of leukemic blasts, blood counts (RBC's, WBC's, and platelets) return to normal.

• The second goal is to maintain the patient in a state of remission and prevent the recurrence of AML.

Prolonged survival in acute myelogenous leukemia is usually observed only in patients in whom complete remission occurs and persists. Patients with acute myelogenous leukemia who have been in complete remission for 3 years or longer are considered potentially cured because after this time the risk of disease relapse is less than 10%. The standard of care for newly diagnosed patients is chemotherapy, which currently is the only treatment capable of producing complete remission in substantial numbers of patients. Chemotherapy, however, is not without risk. Whether chemotherapy is appropriate for all patients is discussed below.

Chemotherapy

Corresponding to the two goals mentioned above, chemotherapy for acute myelogenous leukemia is given in two phases: remission induction and post-remission therapy. In both phases chemotherapy is typically administered for 3-7 days. Chemotherapy reduces both the number of normal and leukemic blasts. Such reduction usually lasts 4-5 weeks. Subsequently, the bone marrow recovers.

If the number of leukemic blasts was reduced sufficiently, the normal blasts resume function, blood counts increase, and usually complete remission is observed. If the decrease in the number of leukemic blasts was insufficient, blood counts fail to return to normal and an excess number of leukemic blasts reappear in the marrow and/or blood. Complete remission indicates that 99.9% of the cancer cells (leukemic blasts) have been destroyed. However, there are still often some "hidden" leukemic cells that remain in the body that can subsequently lead to relapse.

The purpose of the second phase of therapy, called post-remission therapy or consolidation or maintenance therapy is to destroy the remaining leukemic cells. Usually several cycles of chemotherapy are given. Each chemotherapy cycle lasts several days following which blood counts fall, returning to normal 4-6 weeks later at which time another cycle of chemotherapy begins. Typically 4-6 post-remission therapy cycles are given. The doses of chemotherapy given in the post-remission phase are often lower than those used initially for the remission induction phase of treatment. Nevertheless, in both remission induction and post-remission phases blood counts decrease sufficiently so that transfusions of RBCs and platelets are necessary.

The low blood counts associated with chemotherapy predispose patients to potentially fatal infections. This is by far most common during the induction phase both because the patient is not yet in complete remission and because the doses of chemotherapy are higher than those given during the post-remission phase. The likelihood of fatal infection increases with age, and approaches 30% in patients age 70 and over. Another important predictor of death associated with induction chemotherapy is whether the patient is ambulatory when chemotherapy begins; about 15% of patients are not fully ambulatory at this time and as a result have a much higher complication rate.