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Utility of the number needed to treat in paediatric haematological cancer randomised controlled treatment trials: a systematic review
  1. Haroon Hasan1,
  2. Karen Goddard2,
  3. A Fuchsia Howard3
  1. 1 Epi Methods Consulting, Toronto, Ontario, Canada
  2. 2 Department of Radiation Oncology, BC Cancer Agency, Vancouver, British Columbia, Canada
  3. 3 School Of Nursing, University of British Columbia, Vancouver, British Columbia, Canada
  1. Correspondence to Dr A Fuchsia Howard; fuchsia.howard{at}


Objectives The primary objective was to assess the utility of the number needed to treat (NNT) to inform decision-making in the context of paediatric oncology and to calculate the NNT in all superiority, parallel, paediatric haematological cancer, randomised controlled trials (RCTs), with a comparison to the threshold NNT as a measure of clinical significance.

Design Systematic review

Data sources MEDLINE, EMBASE and the Cochrane Childhood Cancer Group Specialized Register through CENTRAL from inception to August 2018.

Eligibility criteria for selecting studies Superiority, parallel RCTs of haematological malignancy treatments in paediatric patients that assessed an outcome related to survival, relapse or remission; reported a sample size calculation with a delta value to allow for calculation of the threshold NNT, and that included parameters required to calculate the NNT and associated CI.

Results A total of 43 RCTs were included, representing 45 randomised questions, of which none reported the NNT. Among acute lymphoblastic leukaemia (ALL) RCTs, 29.2% (7/24) of randomised questions were found to have a NNT corresponding to benefit, in comparison to acute myeloid leukaemia (ALM) RCTs with 50% (3/6), and none in lymphoma RCTs (0/13). Only 28.6% (2/7) and 33.3% (1/3) had a NNT that was less than the threshold NNT for ALL and AML, respectively. Of these, 100% (2/2 ALL and 1/1 AML) were determined to be possibly clinically significant.

Conclusions We recommend that decision-makers in paediatric oncology use the NNT and associated confidence limits as a supportive tool to evaluate evidence from RCTs while placing careful attention to the inherent limitations of this measure.

  • leukaemia
  • lymphoma
  • paediatric oncology
  • numbers needed to treat
  • clinical trials

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  • Patient consent for publication Not required.

  • Contributors AFH, KG and HH conceived and designed the study. HH collected and analysed the data. AFH and HH wrote the first drafts of the manuscript, and all authors contributed to subsequent drafts. All authors had full access to all of the data in the review and take responsibility for the integrity of the data and the accuracy of the data analysis.

  • Funding Funding support was provided by the University of British Columbia School of Nursing to conduct this systematic review.

  • Disclaimer The funder played no role in study design, collection, analysis, interpretation of data, writing of the report or in the decision to submit the paper for publication. They accept no responsibility for the contents.

  • Competing interests None declared.

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Data sharing statement Unpublished data will be made available upon request to the corresponding author.

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