Mismatch Between Cancer Burden and Clinical Trial Activity in the European Union: Analysis of Incidence, per Capita Indicators and Commercial Versus Non-Commercial Studies

Introduction: Cancer represents one of the greatest public health challenges in Europe. Clinical trials play a key role in the development of new diagnostic and treatment methods, but their geographic distribution may not reflect the true epidemiological burden. The aim of this study was to assess the relationship between the incidence of selected cancers and clinical trial activity in European Union countries, with particular emphasis on commercial and non-commercial trials, as well as changes over time. Materials and Methods: Data on clinical trials conducted in European Union countries in 2012, 2014, 2017, and 2022 were analyzed. Epidemiological data were obtained from the GLOBOCAN and Global Burden of Disease databases, while clinical trial data were obtained from the EU Clinical Trials Register. Overall cancer incidence and selected cancer types, namely breast cancer, lung cancer, colorectal cancer, and prostate cancer, were analyzed. Clinical trial activity rates were calculated relative to incidence and population size (per capita). Pearson and Spearman correlation analyses were performed, and 95% confidence intervals and p-values were calculated for the principal correlations. Time trends were also assessed. The results are presented in the form of tables, figures, and maps. Results: Clinical trial activity in oncology varied considerably across European Union countries. Commercial trials were consistently more common than non-commercial trials and showed a more pronounced increase in activity during the analyzed period. Correlations between cancer incidence and the number of clinical trials varied depending on cancer type, year of analysis, and sponsor type. The strongest associations were observed in 2022 for commercial trials, particularly for colorectal cancer (Pearson’s r = 0.865, 95% CI: 0.723–0.937, p < 0.001) and lung cancer (Pearson’s r = 0.853, 95% CI: 0.701–0.931, p < 0.001). Spearman analysis confirmed strong rank-based associations in 2022, especially for lung cancer (ρ = 0.971, 95% CI: 0.937–0.987, p < 0.001). Analysis of trial activity indicators indicated a mismatch between disease burden and the intensity of research activity in some countries and oncology areas. Conclusions: Clinical trial activity in oncology in European Union countries does not always reflect the actual cancer burden. The observed differences between commercial and non-commercial trials and between individual cancer types may indicate a research gap and the need for more balanced clinical trial planning in the European Union.