Data analysis

A PRISMA flow diagram was used to illustrate the literature search results and study selection process. Outcomes were categorised according to the essential steps of early cancer diagnosis as specified in the WHO Guide to Cancer Early Diagnosis.²⁴ Plans to conduct a meta-analysis were not feasible as studies were not quantitatively comparable in terms of interventions and reported outcomes. Instead, a thematic narrative synthesis approach was used to aggregate and analyse relevant findings. Plans to assess the certainty of reviewed evidence using the Grades of Recommendation Assessment, Development and Evaluation approach³⁹ were not feasible for similar reasons. A table summarising findings from each included study was presented. JM and FMW reviewed the analysed data for accuracy and consistency with protocol.