Real-World Data: Applications and Relevance to Cancer Clinical Trials.

Randomized controlled trials (RCTs) are the gold standard for comparative-effectiveness research (CER). Since the 1980s, there has been a rise in the creation and utilization of large national cancer databases to provide readily accessible "real-world data" (RWD). This review article discusses the role of RCTs in oncology, and the role of RWD from the national cancer database in CER. RCTs remain the preferred study type for CER because they minimize confounding and bias. RCTs have challenges to conduct, including extensive time and resources, but these factors do not impact the internal validity of the result. Generalizability and external validity are potential limitations of RCTs. RWD is ideal for studying cancer epidemiology, patterns of care, disparities in care delivery, quality-of-care evaluation, and applicability of RCT data in specific populations excluded from RCTs. However, retrospective databases with RWD have limitations in CER due to unmeasured confounders and are often suboptimal in identifying causal treatment effects.