Acute promyelocytic leukaemia is highly frequent among acute myeloid leukaemias in Brazil: a hospital-based cancer registry study from 2001 to 2012

The WHO classification that defines subtypes of acute myeloid leukaemias (AMLs) is relatively unexplored at the population-based level. This study aimed to examine the frequency of acute promyelocytic leukaemia (APL or AML-M3) in Brazil. Data were extracted from 239 cancer centres (2001–2012) and categorized according to the International Classification of Diseases for Oncology (CID-O 3.0) and WHO classification (n = 9116). CID-O3 code 9866 identified 614 APL patients. AML not otherwise specified (NOS) was frequent, and the APL group represented the main subtype specified. The mean age of APL was lower than that of other AMLs (31.5, standard deviation (SD) 18.6 versus 40.9, SD 24.6; p < 0.001); there was a high frequency of APL in the 13–21-year-old (11.8 %) and ≤12.9-year-old (6.4 %) age groups. Time taken to begin treatment (as ≤14 days versus >14 days) and induction death rate were lower in APL than in other AML subtypes (p < 0.001). This report provides additional evidence on the distribution of APL among cases of AML in Brazil.