Mapping eligibility criteria in oncology target trial emulations using real-world data: a scoping review

Target trial emulations often face challenges in accurately identifying the intended target population within real-world data (RWD) because eligibility criteria cannot always be directly mapped to available variables. This scoping review aimed to systematically characterize the proportion of eligibility criteria from oncology target trials that are successfully mapped to their emulated counterparts and to describe the approaches used for this mapping.

We searched MEDLINE for peer-reviewed studies published between January 1, 2016, and April 23, 2025, that were designed to emulate oncology drug intervention trials using RWD. For each target trial emulation, we recorded design elements, database types, eligibility criteria, and methodological details. We identified how each target trial eligibility criterion was mapped to available RWD. For each applicable criterion, we assessed whether it was explicitly represented and conceptually consistent with the target trial; criteria meeting both were classified as mapped. Eligibility criteria were categorized into 11 domains representing key demographic, clinical, and safety considerations.

Our search identified 200 studies, of which 47 reported the results of 74 individual target trial emulations. Of these 74, 42 (56.8%) were emulations of actual clinical trials and 32 (43.2%) were emulations of hypothetical target trials. Most target trial emulations used registry data (30, 40.5%) or electronic health records (29, 39.2%) as their primary data sources. Emulations of actual clinical trials specified a median of 29 (interquartile range [IQR] 25.0-34.0) eligibility criteria and mapped a median of 35.5% (IQR 27.3%-40.6%) of these criteria per emulation, whereas emulations of hypothetical trials specified a median of 5.5 (IQR 4.3-12.8) eligibility criteria and mapped a median of 91.7% (IQR 70%-100%) of these criteria per emulation. Among 1,222 individual criteria, demographic criteria were most frequently mapped (46, 93.9%), while safety and concomitant risk-related criteria were least frequently mapped (7, 3.7%). The most common mapping method was direct mapping using administrative coding systems (37, 72.5%); no studies reported using common data models or computational methods.

This scoping review of oncology target trial emulations found substantial heterogeneity in how eligibility criteria were mapped, with potential implications for emulation results. These findings highlight the need for greater transparency and for methods that extend beyond reliance on structured administrative codes.