Racial/ancestral diversity in 174 toxicity-related radiogenomic studies: A systematic review

Purpose: This study systematically reviews the distribution of racial/ancestral features and their inclusion as covariates in genetic-toxicity association studies following radiation therapy. Materials and Methods: Original research studies associating genetic features and normal tissue complications following radiation therapy were identified from PubMed. The distribution of radiogenomic studies was determined by mining the statement of country of origin and racial/ancestrial distribution and the inclusion in analyses. Descriptive analyses were performed to determine the distribution of studies across races/ancestries, countries, and continents and the inclusion in analyses. Results: Among 174 studies, only 23 with a population of more one race/ancestry which were predominantly conducted in the United States. Across the continents, most studies were performed in Europe (77 studies averaging at 30.6 patients/million population [pt/mil]), North America (46 studies, 20.8 pt/mil), Asia (46 studies, 2.4 pt/mil), South America (3 studies, 0.4 pt/mil), Oceania (2 studies, 2.1 pt/mil), and none from Africa. All 23 studies with more than one race/ancestry considered race/ancestry as a covariate, and three studies showed race/ancestry to be significantly associated with endpoints. Conclusion: Most toxicity-related radiogenomic studies involved a single race/ancestry. Individual Participant Data meta-analyses or multinational studies need to be encouraged.

Automated summary

The study reviewed the distribution of racial/ancestral features and their inclusion in genetic-toxicity association studies following radiation therapy. Most studies involving toxicity-related radiogenomic studies were conducted in Europe and North America, with individual races/ancestries being considered as covariates in some cases. Encouraging multinational studies or Individual Participant Data meta-analyses is necessary to further advance research in this field.