Clinicopathologic analysis of acute myeloid leukemia in a single institution: biphenotypic acute myeloid leukemia may not be an aggressive subtype.

BACKGROUND Most acute leukemias are classified as lymphoid or myeloid lineages by standard microscopic morphology, cytochemistry and a panel of immunologic markers. The World Health Organization classification of acute leukemia incorporates morphologic, cytogenetic, immunologic and clinical features to define the entities that are biologically homogeneous and that have clinical relevance. The purpose of this study was to determine the clinicopathologic characteristics of acute myeloid leukemia (AML) in Taiwan. METHODS Archival tissues from 70AML patients during the period of 1995 to 2003 were retrieved. Histologic subtype was classified, defined by World Health Organization classification. Clinical data, including age, gender, treatment and outcome, were scrutinized. RESULTS There were 37 males and 33 females. The median age at onset of disease was 49 years (range, 2-78 years), which was younger in biphenotypic AML (23.5 years) and older in multilineage dysplasia-related AML (61 years). There were 9 cases (13%) with recurrent cytogenetic abnormality, 7 (10%) multilineage dysplasia-related, 7 (10%) therapy-related, 39 (56%) not other categorized and 8 (11%) of ambiguous lineage. The 2- and 5-year overall survival rates of AML were 26.5% and 20.6%, respectively. Histologic subtype was a significant parameter to determine survival (p < 0.05). The median survivals of therapyrelated, multilineage dysplasia-related and biphenotypic AML were 2 months, 9 months and 30.5 months, respectively. CONCLUSION This was a clinicopathologic study of AML in Taiwan. Histologic subtype plays a significant prognostic role. Multilineage dysplasia- and therapy-related AML have worse prognosis. Biphenotypic AML may not be an aggressive subtype.