Karen L Barton

This systematic review and meta-analysis were conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) recommendations (Fig. 1) [11, 12]. Primary studies published in the English language between January 2000 and April 2021 were retrieved from PubMed, Scopus, and Embase. We focused on studies published after 2000 to account for the updated research based on breast tumor classifications and different subtypes.

Having an explicit research strategy, against which research gains may be measured, is one of the markers of a ‘vital and sustainable’ research environment as stipulated by the UK Research Excellence Framework 2014.1 Indeed, Chalmers and Glasziou2 have estimated that up to 85% of research investment is wasted because of low-priority research questions that do not meet stakeholder needs.