Cancer Health Center
Chronic Myelogenous Leukemia Treatment - Treatment Option Overview
Note: Some citations in the text of this section are followed by a level of evidence. The PDQ editorial boards use a formal ranking system to help the reader judge the strength of evidence linked to the reported results of a therapeutic strategy. (Refer to the PDQ summary on Levels of Evidence for more information.)
Treatment of patients with chronic myelogenous leukemia (CML) is usually initiated when the diagnosis is established, which is done by the presence of an elevated white blood cell (WBC) count, splenomegaly, thrombocytosis, and identification of the BCR/ABL (breakpoint cluster region/Abelson) translocation.[1] The optimal frontline treatment for patients with chronic-phase CML is the subject of active clinical evaluation but involves specific inhibitors of the BCR/ABL tyrosine kinase. In a randomized trial comparing imatinib mesylate with interferon plus cytarabine, with 5 years' median follow-up, imatinib mesylate induced complete cytogenetic responses in more than 80% of newly diagnosed patients; in addition, the annual rate of progression to accelerated phase or blast crisis dropped from 2% to less than 1% in the fourth year on the imatinib arm.[2][Level of evidence: 1iiDiii] However, most of these continually responding patients still showed detectable evidence of the BCR/ABL translocation by the most sensitive measurement of reverse transcriptase-polymerase chain reaction (RT-PCR).[3,4,5] The clinical implication of this finding after 10 years or more is unknown, but these results have changed clinical practice. Although evidence-based survival benefits are unavailable because of crossover in randomized trials, the preferred initial treatment for newly diagnosed patients in chronic phase involves imatinib mesylate.[6,7] In addition, the overall survival rate for all patients at 5 years is 89%, with fewer than 50% of all deaths (4.5%) caused by CML. Higher doses of imatinib, alternative tyrosine kinase inhibitors such as dasatinib or nilotinib, and allogeneic stem cell transplantation (SCT) are implemented for suboptimal response or progression and are under clinical evaluation as frontline approaches.[8,9,10,11,12,13,14,15]
The only consistently successful curative treatment of CML beyond 10 years' follow-up has been allogeneic bone marrow transplantation (BMT) or SCT.[16] Long-term data beyond 10 years of therapy are available, and most long-term survivors show no evidence of the BCR/ABL translocation by any available test (e.g., cytogenetics, RT-PCR, or fluorescent in situ hybridization [FISH]). Many patients, however, are not eligible for this approach because of age, comorbid conditions, or lack of a suitable donor. In addition, substantial morbidity and mortality result from allogeneic BMT or SCT; a 15% to 30% treatment-related mortality can be expected, depending on whether a donor is related and on the presence of mismatched antigens.[16]
Long-term data are also available for patients treated with interferon-alpha.[17,18,19] Approximately 10% to 20% of these patients have a complete cytogenetic response with no evidence of BCR/ABL translocation by any available test, and the majority of these patients are disease-free beyond 10 years.[16] Maintenance of therapy with interferon is required, however, and some patients experience side effects that preclude continued treatment.
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Chronic Myelogenous Leukemia Treatment Topics
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