Fig. 4: Recruiting cancer trials versus cancer burden for regions and income groups.

This figure presents the number of recruiting cancer clinical trials alongside burden-adjusted metrics across World Bank income groups and WHO regions. ‘Recruiting trials per prevalence unit’ refers to the number of trials per 100,000 prevalent cancer cases, while ‘recruiting trials per mortality unit’ refers to the number of trials per 100,000 cancer deaths. These ratios provide a direct measure of research activity relative to population-level disease burden and highlight inequities in clinical trial allocation. Higher ratios reflect greater research investment per unit of burden. Shading reflects the range of values from high (red) to low (blue) for ease of comparison.