[Impact of time to hematological response on survival in patients treated with azacytidine: a single-center retrospective study].

We analyzed 95 cases of MDS (n=78), CMML (n=8) and AML (n=9) with blast counts of <30%, treated by AZA since March 2011, for a possible association of hematological improvement (HI) and overall survival duration (OS). We defined four categories as follows: stable disease (SD): no exacerbation of disease even if HI was not achieved after nine cycles of AZA treatment; early and late response (ER, LR): achievement of HI within and beyond three cycles, respectively; and drop out (DO): termination of treatment within nine cycles due to disease progression or complication without obtaining HI. OS was significantly longer in the LR than in the ER. The OS of ER was significantly shorter than that of the SD group. Patients in ER group who relapsed had significantly shorter survival than those who were able to maintain HI. Additionally, 3 out of 11 SD cases achieved HI after 10 cycles. We conclude that AZA should be continued until disease progression besides an achievement of HI.