Outcome
The outcome and time to death is reported in table 4. Of the 110 patients included in this analysis, 72 (65.5 %) reached complete remission (CR) by day 36, 7 (6.4 %) did not reach CR by day 36 and the remaining 31 (28.2 %) patients died before the second bone marrow examination. Because in many instances death was attributed to infection and bleeding, the documentation of the disease state with a bone marrow was not always performed. We therefore focused our analysis on the estimated 3 year OS, which for the whole patient cohort was 34.9 % (SE = 4.6), as illustrated in (Fig 1A).
As expected, the estimated 3 year OS was significantly higher for the 47 patients allocated to the SR group with 50.5% (SE = 7.4) compared to the HR group (23.4 % (SE = 5.4)) (p = 0.012). It is important to note that the majority of all patients (57. 3%) was stratified into the HR group, mostly due to their initial high WBC count or age > 10 years. Estimated 3 year OS was best (51.5% (SE = 7.1)) for patients younger than 10 years with a WBC count under 50 x 109/l and worst (6.3 % (SE = 6.1)) for patients 10 years or older with a WBC count of 50 x 109/l or more, which were significant differences (p = 0.011), as described in (Fig 1B).