Additional chromosome abnormalities confer worse prognosis in acute promyelocytic leukaemia

Acute promyelocytic leukaemia (APL) has been associated with a favourable prognosis in many studies of acute myeloid leukaemia. A series of 54 patients treated at the Royal Marsden Hospital between 1979 and 1996, with APL and the t(15;17) chromosome translocation at pres‐entation, was examined for the effect of additional chromosome abnormalities in their presentation karyotype on survival. The patients were aged between 2 and 62 years with a median age of 31 years. There were approximately equal numbers of males and females. Presentation white cell count ranged from 0.7 to 156 × 109/l with a median of 1.0 × 109/l. 39% of patients (21/54) had additional chromosome abnormalities at presentation. Statistical analyses were performed for factors thought to influence survival such as age, sex, white cell count, and number of courses of chemotherapy required to enter remission. These showed that the presence of additional chromosome abnormalities has an adverse effect on prognosis, independent of other prognostic indicators, reducing it to the level of patients with AML from less‐favourable cytogenetic subgroups. These data indicate that additional therapeutic strategies may be required in patients with APL who demonstrate cytogenetic aberrations over and above the t(15;17) at presentation. The biological basis for the more aggressive nature of these cases remains to be determined.