Systems for grading the strength of recommendations in clinical practice guidelines in oncology

Introduction. In order to improve the applicability of clinical practice guidelines, their authors assign recommendations with grades denoting the degree of conviction regarding their practical application. Nevertheless even within one branch of medicine, significant differences between the grading systems arise. Material and methods. To identify these systems, websites of societies and institutions publishing oncology guidelines were searched. Only high-quality, regularly updated guidelines were included. Results. Five systems were analysed – all incorporate quality of evidence and strength of recommendation, but vary in the methods of their assessment and structure of the scales. Discussion. The described systems depend on the review of data, the quality of which supports the ascribed strength. Systems differ with regard to the methods of assessing the quality, quantity and consistency of evidence, potentially leading to assigning different grades of strength to recommendations based on the same studies. Conclusions. The introduction of unified grading systems across each branch of medicine could aid the development of unambiguous recommendations that are easy to introduce within the healthcare system.