Prognostic impact of discordant results from cytogenetics and flow cytometry in patients with acute myeloid leukemia undergoing hematopoietic cell transplantation

BACKGROUND: Cytogenetics and multicolor flow cytometry (MFC) are useful tools for monitoring outcome of treatment in acute myeloid leukemia (AML). However, no data are available regarding the meaning of results when the 2 tests do not agree.METHODS: The authors of this report analyzed 1464 pairs of concurrent cytogenetics and flow results from 424 patients, before and after hematopoietic cell transplantation, and compared the prognostic impact of discordant and concordant results. RESULTS: Informative discordant results were observed in 22% of patients. Compared with patients who had double-negative test results, either positive result had a significant impact on overall survival and relapse-free survival. The hazard ratios with either positive cytogenetic results or positive MFC results pretransplantation were 3.1 (P = .009) and 2.5 (P = .0008), respectively, for reduced overall survival and 2.7 (P = .01) and 4.1 (P < .0001), respectively, for decreased recurrence-free survival. Similar findings were obtained post-transplantation. Molecular cytogenetics, ie, fluorescence in situ hybridization (FISH), added value to the evaluation of discordant cases. CONCLUSIONS: The detection of residual AML by either cytogenetics or flow cytometry in patients who underwent hematopoietic cell transplantation predicted early relapse and shortened survival. Cancer 2012; 118: 2411-19. (C) 2011 American Cancer Society.