According to results recently presented at the 38th Annual Meeting of the American Society of Clinical Oncology, prolonged maintenance therapy may reduce cancer recurrences compared to intensive consolidation therapy for patients with acute myeloid leukemia with a poor prognosis.
Acute myeloid leukemia (AML) is a cancer of the bone marrow and blood characterized by the rapid uncontrolled abnormal growth of immature white blood cells known as myelocytes. The disease is more common in adults than in children, with the average age at diagnosis being over 65 years. Treatment for AML consists of remission induction, which is initial therapy utilized to induce a remission (disappearance of cancer), followed by consolidation therapy, which is therapy used during a complete remission to kill any cancer cells that may have remained following previous therapy. Over the past two decades, consolidation therapy involving a shorter course of intensive chemotherapy has been increasingly utilized in favor of longer-term, less-intensive maintenance chemotherapy.
Specific disease and patient characteristics that are associated with overall prognosis have become increasingly defined and researchers are continually attempting to determine which variables respond more favorably to certain treatment regimens. AML patients with a poor prognosis have at least one of the following criteria: over 60 years of age, specific unfavorable genetic alterations, a high level of immature white blood cells (blasts) at 16 days following initiation of treatment and high levels of the enzyme lactate dehydrogenase (LDH). AML patients with a favorable prognosis do not possess any of these criteria.
The German AMLCG group conducted a clinical trial in the 1980’s to compare intensive consolidation chemotherapy to longer maintenance chemotherapy in patients with AML. This trial involved 837 patients, 60% of whom had a poor prognosis. Patients were treated with consolidation therapy consisting of either short-term, intensive chemotherapy or lower-doses of maintenance chemotherapy for 3 years. Overall, the average cancer-free survival was 19 months for patients treated with long-term maintenance, compared to only 12 months for patients treated with intensive consolidation therapy. Five years following therapy, 31% of patients treated with maintenance therapy were alive and cancer-free, compared to only 24% of patients treated with intensive consolidation therapy. In the poor prognosis group, the average cancer-free survival was 12 months for patients treated with maintenance therapy, compared to 10 months in patients treated with intensive therapy. Twenty-four percent of poor-prognosis patients treated with maintenance therapy remain cancer-free, compared to only 12% of patients treated with intensive consolidation therapy. However, in the group of patients with a favorable prognosis, the average cancer-free survival was 27 months for patients treated with maintenance therapy, compared to 38 months for patients treated with intensive consolidation therapy. Thirty-two percent of good-prognosis patients treated with maintenance therapy remain alive and cancer-free, compared to 48% treated with intensive consolidation therapy. Side effects from treatment were more severe for patients treated with intensive consolidation therapy.
These results indicate that long-term, lower-dose maintenance therapy may reduce cancer recurrences compared to intensive consolidation therapy for poor-prognosis patients with AML. This is important, as the majority of patients diagnosed with AML are over the age of 60, which automatically places them in the poor-risk category and elderly patients often have difficulties tolerating intensive chemotherapy. Since patients were allowed to receive different therapy if their cancer progressed, it is difficult to establish survival benefits between the two treatment groups, however, the rate of cancer-free survival in poor-prognosis patients treated with maintenance therapy is promising. Patients with poor-prognosis AML may wish to speak with their physician about the risks and benefits of maintenance therapy or the participation in a clinical trial evaluating novel therapeutic approaches. Two sources of information regarding ongoing clinical trials include the National Cancer Institute (cancer.gov) and www.eCancerTrials.com. eCancerTrials.com also provides personalized clinical trial searches on behalf of patients.
Reference: Büchner T, Hiddemann W, Berdel WE, et al. Prolonged maintenance treatment is superior to intensive consolidation and improves long-term prognosis even in the poor prognostic subgroup of patients with acute myeloid leukemia (AML). Proceedings of the 38th Annual Meeting of the American Society of Clinical Oncology. 2002;21:abstract 1046.
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