Unfavorable, complex, and monosomal karyotypes: the most challenging forms of acute myeloid leukemia.

In acute myeloid leukemia, the karyotype of the leukemic cell is the most powerful predictor of treatment outcome. Approximately 30% of cases of AML have an unfavorable karyotype, and if treated with conventional chemotherapy, a complete response rate of about 50% and a 5-year overall survival of 10% to 20% are expected. Of those in the unfavorable group, almost half will have a complex karyotype, which is associated with a poorer outcome, and 40% of those will have a monosomal karyotype, which carries an even worse prognosis. The best chance for cure for patients with an unfavorable karyotype is seen in those who achieve a complete response and proceed to allogeneic transplant. For patients who are not candidates for aggressive therapy, preliminary data suggest that outcomes at least equivalent to those seen with standard chemotherapy can be obtained using azacitidine or decitabine.