Significance of cytogenetic abnormalities in acute myeloid leukaemia

To evaluate the role of karyotype in acute myeloid leukaemia (AML) as a predictor of response to induction chemotherapy.

A cross-sectional study was carried out at the department of Pathology and Oncology, Aga Khan University Karachi from January 2003 to January 2005. Newly diagnosed patients with denovo AML admitted to the hospital were included in the study. Diagnosis of AML was based on FAB criteria, immunophenotyping and cytogenetic studies. They were treated according to standard protocols (combination of anthracycline and cytarabine -3+7) and those who had acute promyelocytic leukaemia additionally received all- trans retinoic acid (ATRA).

A total of 56 patients were enrolled, 4 were excluded due to inadequate cytogenetic analysis and the remaining patients entered the study protocol. There were 32 males and 20 females with mean age of 31.3 years (range 9 months to 73 years). Thirty-five (67.3%) patients had normal karyotype while 17 (32.7%) were found to have cytogenetic abnormalities. Eleven patients did not receive treatment at our hospital. Half of the (51.2%) patients out of remaining 41 achieved complete remission on bone marrow examination after receiving induction chemotherapy. In favourable risk group 3/3 (100%) achieved complete remission (CR) while 15/32 (46.9%) in intermediate risk group and 3/6 (50%) in unfavourable risk group. There was low CR rate in patients with high white cell counts.

The frequency of cytogenetic abnormalities in AML and response to induction chemotherapy was low when compared with international data possibly due to the small sample size. However, there was a clear difference in CR rates between favourable and unfavourable risk groups.