Geographic differences in the incidence of cytogenetic abnormalities of acute myelogenous leukemia (AML) in Spain.

The incidence of chromosomal abnormalities in acute myeloid leukemia (AML) differs according to geographical regions in Spain. We analyse 1,271 consecutive patients diagnosed of AML between 1995 and 2002 in three different regions of Spain: northern, central and southern. There were 624 males (55%) and 505 females (45%). Age ranged between 1 month and 94 years with a median of 61 years. Abnormal karyotypes were observed in 64% of cases. Numerical abnormalities as sole cytogenetic changes were detected in 15% of patients, while structural aberrations were present in 28% of cases, and both abnormalities were found in 22% of patients. A significantly higher proportion of t(15;17) was observed in the south of Spain (21.6%) than in the central (17%) or northern regions (12.6%) (p=0.03). By contrast, patients from the south of Spain showed lower incidence of t(8;21) (0%, compared to 1.6% and 3.6% in central and northern areas, respectively, p=0.04). These differences were maintained in the age-adjusted analysis. Trisomy 8 showed similar incidence in southern and central areas, while the incidence in the northern area was lower (14% and 10%, respectively, p=0.04). Other chromosomal abnormalities, such as inv(16) or 11q23 rearrangements, were found at similar frequencies in the three regions.