The retrospective clinical study, performed jointly by the Centre for Children's Cancer and Blood Disorders (CCC&BD)at Sydney Children's Hospital and Children's Cancer Institute Australia, was recently published in the international Journal of Clinical Oncology. Researchers investigated how both normal and malignant blood cells of children with Acute Lymphoblastic Leukaemia (ALL) responded to the first phase of chemotherapy treatment (induction).
Dr Stephen Laughton and co-investigators found that a slow rate of recovery of normal white blood cells at the end of induction, as shown by a low absolute neutrophil count (ANC), was highly predictive of relapse.
"Many traditional predictive factors have lost their significance over time, so there is a real need to find new markers that can be used to identify high-risk patients," said A/Prof Glenn Marshall, Director of the CCC&BD and Head of the Molecular Carcinogenesis Program at CCIA.
"Our work is the first to highlight the fact that the differences in the responses of normal and malignant blood cells may vary between individuals, and, moreover, that this information might be used to adjust therapy on an individual basis."
The study also found, as investigators expected, that high levels of leukaemic cells surviving initial treatment, minimal residual disease (MRD), indicated a high risk of relapse. A technique to determine levels of MRD was pioneered at CCIA.
However, the two prognostic factors (low ANC and high MRD) were found to predict outcome by distinct mechanisms and to have independent prognostic significance.