Abstract
BACKGROUND.
Clonal cytogenetic abnormalities (CCA) were detected in Philadelphia chromosome (Ph)‐negative cells in some patients with chronic myeloid leukemia (CML) who attained a cytogenetic response to imatinib mesylate. In some patients, CCA/Ph‐negative status was associated with myelodysplasia or acute myeloid leukemia. The objective of the current study was to determine the prognostic impact of CCA/Ph‐negative cells.
METHODS.
The authors compared the pretherapeutic risk factors (Kruskall‐Wallis test), exposure to cytotoxic drugs (chi‐square test), and overall and progression‐free survival (Kaplan‐Meyer and logistic regression analysis, respectively) of 515 patients with mostly chronic‐phase CML who were treated with imatinib mesylate after failure of interferon‐α according to whether they attained a major cytogenetic response (MCR) (n = 324 patients), an MCR with CCA/Ph‐negative status (n = 30 patients), or no MCR (n = 161 patients).
RESULTS.
CCA/Ph‐negative status most frequently involved chromosomes Y, 8, and 7. No significant differences in pretherapeutic risk factors were detected between patients who attained an MCR with and without CCA/Ph‐negative cells, except that exposure to alkylating agents was more frequent in patients with CCA/Ph‐negative cells, and overall and progression‐free survival were identical. With a median follow‐up of 51 months, only 2 patients developed myelodysplastic syndromes (MDS).
CONCLUSIONS.
The overall prognosis for patients who had CML with CCA/Ph‐negative status was good and was driven by the CML response to imatinib mesylate. Isolated CCA/Ph‐negative cells in the absence of morphologic evidence of MDS do not justify a change in therapy. Cancer 2007. © 2007 American Cancer Society.