Standard treatment for patients with acute myeloid leukemia (AML) begins with initial moderate-dose chemotherapy that usually induces a remission (no detectable cancer cells in the body). During this remission, patients receive further treatment, called consolidation, in order to decrease the risk for cancer recurrence. Consolidation may consist of multiple cycles of intensive chemotherapy and/or high-dose chemotherapy and stem cell transplantation. May patients will be treated with both, however, results from a recent study indicate that consolidation chemotherapy prior to allogeneic SCT may not be necessary to achieve optimal results.

Acute myeloid leukemia is a cancer of the white blood cells. The bone marrow contains early blood-forming cells, called stem cells, which grow and mature into 3 blood cell types: red blood cells, which provide Oxygen to tissues, platelets, which aid in blood clotting, and white blood cells, which fight infection. AML is characterized by the rapid uncontrolled growth of immature white blood cells in the bone marrow, resulting in excess accumulation of these cells. These leukemia cells crowd the bone marrow, suppressing formation and function of other blood cells, and ultimately invade other parts of the body including the blood, lymph system, and vital organs. AML is a rapid growing cancer and treatment must be aggressive for an optimal chance of cure.

Chemotherapy, the treatment of choice for AML, targets and kills rapidly dividing cells, such as cancer cells. Although chemotherapy is effective at killing cancer cells, treatment does not differentiate between cancer cells and healthy cells. High-dose chemotherapy kills more cancer cells than lower dose conventional chemotherapy. Unfortunately, high-dose chemotherapy also kills more normal cells, especially the blood producing stem cells in the bone marrow. When these cells reach critically low levels, complications such as anemia, infection and bleeding can occur. The treatment strategy utilizing stem cell transplantation is an attempt to restore the blood producing stem cells after high-dose chemotherapy has reduced them to dangerously low levels. In addition to restoring blood cell levels, infused cells may actually attack and kill leukemia cells. This immune reaction is called the graft-versus leukemia effect. The process of allogeneic stem cell transplantation includes the collection of stem cells from a donor that are later infused into the patient after the patient’s high-dose chemotherapy treatment. Recently, there has been controversy over whether or not high-dose consolidation chemotherapy administered before SCT is necessary to achieve optimal results or whether it merely increases the risk of side effects from SCT.

Researchers recently evaluated 431 patients with AML who received consolidation treatment with allogeneic stem cells transplant while in their first remission. Prior to transplant, patients received additional consolidation therapy consisting of high-dose chemotherapy, moderate-dose chemotherapy or no additional treatment. All patients were treated with an allogeneic SCT. The results of the study shoed that there was no significant difference in survival if patients were treated with high-dose chemotherapy, medium-dose chemotherapy, or no consolidation therapy prior to allogeneic SCT. Importantly, high-dose chemotherapy prior to SCT did not lower the rate of cancer recurrence in comparison to those who received no consolidation treatment. High-dose chemotherapy also did not appear to increase mortality rates due to side effects from the transplant.

From these findings, these doctors concluded that there does not appear to be benefit from additional consolidation treatment administered before an allogeneic SCT in patients with AML that are in first remission. Thus, for patients with a suitable stem cell donor, allogeneic SCT may be performed immediately after recovery from remission induction chemotherapy. Persons who have AML may wish to speak with their doctor about the risks and benefits of this treatment strategy or about the participation in a clinical trial utilizing other promising new strategies. Two sources of information on ongoing clinical trials that can also be discussed with a doctor include comprehensive, easy to use clinical trials listing services provided by the National Cancer Institute (cancer.gov) and eCancerTrials.com. eCancerTrials.com also performs personalized clinical trial searches on behalf of patients. (Blood, Vol 96, No 4, pp 1254-1258, 2000)

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