Advances in therapy for childhood non-B-lymphoblastic leukaemia

Impact of single nucleotide polymorphisms of cytarabine metabolic genes on drug toxicity in childhood acute lymphoblastic leukemia

BACKGROUND

Cytarabine (cytosine arabinoside, ara-C) is a chemotherapeutical agent used in the treatment of pediatric acute lymphoblastic leukemia (ALL). Adverse drug reactions, such as interpatient variability in sensitivity to ara-C, are considerable and may cause difficulties during chemotherapy. Single nucleotide polymorphisms (SNPs) can play a significant role in modifying nucleoside-drug pharmacokinetics and pharmacodynamics and thus the development of adverse effects. Our aim was to determine whether polymorphisms in genes encoding transporters and enzymes responsible for the metabolism of ara-C are associated with toxicity and clinical outcome in a patient population with childhood ALL.

PROCEDURE

We studied 8 SNPs in the CDA, DCK, DCTD, SLC28A3, and SLC29A1 genes in 144 patients with childhood acute lymphoblastic leukemia treated according to ALLIC BFM 1990, 1995 and 2002 protocols.

RESULTS

DCK rs12648166 and DCK rs4694362 SNPs were associated with hematologic toxicity (OR = 2.63, CI 95% = 1.37-5.04, P = 0.0036 and OR = 2.53, CI 95% = 1.34-4.80, P = 0.0044, respectively).

CONCLUSIONS

Our results indicate that DCK polymorphisms might be important genetic risk factors for hematologic toxicity during ALL treatment with ara-C. Individualized chemotherapy based on genetic profiling may help to optimize ara-C dosing, leading to improvements in clinical outcome and reduced toxicity.

Pediatric oncology nursing: providing care through decades of change

Pediatric oncology nursing practice has evolved over the years as new technology and trends in health care have precipitated change. Three pediatric oncology nursing leaders share their perspectives on nursing practice as it relates to treatment of a child with leukemia during four different points in time. Their comments illustrate the challenges, resources, and rewards. Their reflections, combined with a survey of the literature over the past half a century, show the dramatic impact of advances in supportive care on the practice of caring for a child with cancer. It is also evident that as the cure rate has increased, so have the efforts to improve quality of life. What has transcended time is the delivery of consistent and compassionate care, the education of patients and families, and the dedication to advocacy and support.

Intensification of treatment and survival in all children with lymphoblastic leukaemia: results of UK Medical Research Council trial UKALL X. Medical Research Council Working Party on Childhood Leukaemia

The UK Medical Research Council trial MRC UKALL X was designed to investigate the benefit of one or two courses of additional intensification therapy in children with acute lymphoblastic leukaemia receiving standard treatment. From 1985 to 1990 1612 children, comprising more than 90% of eligible cases in the UK, were treated with intensive induction therapy, central nervous system directed therapy with cranial irradiation and intrathecal methotrexate, and continuing treatment for 2 years. 1171 children were randomised to receive additional intensification therapy at 5 weeks, 20 weeks, both, or neither. At follow-up of at least 3 years disease-free survival for all children at 5 years was 62% (95% confidence interval [Cl] 60.0-64.4), a significant improvement over the 56% (53.0-59.6) found in the preceding MRC UKALL trial. The 5-year disease-free survival was 71% (65.5-76.1) for children randomised to two blocks of intensification therapy, this being significantly better than the 62% (56.6-68.0), 61% (55.7-67.1), and 57% (50.9-62.7) rates for the groups randomised to one intensification block at 5 weeks, one at 20 weeks, and no intensification, respectively. The benefits of intensification therapy were seen irrespective of clinical factors known to influence outcome such as age, sex, and initial leucocyte count. We conclude that the addition of two courses of intensification therapy has produced a 14% improvement in disease-free survival and an 11% improvement in overall survival for the randomised patients. This additional treatment is of benefit to all children with acute lymphoblastic leukaemia, even those traditionally deemed at lower risk of relapse.