Systematic versus narrative reviews: how do they compare and what does that tell us about their role in scientific exchange?

<b>Objective:</b> To understand how systematic and narrative reviews differ in terms of research objective, scope, conclusions, and reporting. <br><br><b>Research design and methods: </b>We conducted a systematic review using Embase and MEDLINE databases to identify systematic reviews, narrative reviews, and meta-analyses on prostate cancer published in English in the period 2010-2015.<br><br><b>Results: </b>The customized search identified 469 abstracts. After manual screening, we identified 4 narrative and 6 systematic reviews covering prostate-specific antigen-based screening, androgen deprivation therapy, and treatments for bone metastases. None had industry or agency involvement. Whereas systematic reviews focused on narrowly defined treatment comparisons, narrative reviews were broad and included pharmacological class-based questions and clinical opinion on treatment approaches. Only 1 narrative review compared treatments, and this came to a different conclusion from the comparable systematic review owing to concerns over cost.<br><br><b>Conclusions:</b> Comparative efficacy assessments are quantitatively validated in the systematic reviews focus on individual comparators, and are more comprehensively reported than in the narrative reviews. Narrative reviews predominantly make pharmacological class-based assessments. While there are continuing roles for both narrative and systematic reviews in scientific discourse, they appear to be addressing different research needs. Apparently, specificity of the decision problem and the depth of scientific evidence available determine the best approach