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RCT Enrollment Itself Associated with Different Post-Prostatectomy Management Than Real-World Care
Patients enrolled in the G-MINOR randomized controlled trial had substantially higher treatment-free survival at two years compared to propensity score matched real-world patients from the same registry, at 84% versus 74% (p < 0.001), indicating that trial participation itself was associated with meaningfully different clinical management. This finding suggests that the generalizability gap between RCTs and routine practice may stem not only from who enters trials, but from how patients are managed once enrolled.
What Was Studied
This study examined whether patients with high-risk prostate cancer managed after radical prostatectomy were treated differently depending on whether they were enrolled in the G-MINOR RCT — a trial evaluating how a genomic classifier influenced post-surgical treatment decision-making — compared to similar patients receiving routine care outside the trial. The primary outcomes were rates of secondary treatment (adjuvant or salvage therapy) and time to that treatment.
How It Was Studied
This was a cohort comparison study embedded within an existing clinical registry, the Michigan Urological Surgery Improvement Collaborative (MUSIC), in which the G-MINOR trial was conducted. A total of 1,690 patients were included across three groups: 338 enrolled in G-MINOR, 1,014 contemporary MUSIC patients who were eligible but not enrolled, and 338 pre-trial MUSIC patients matched to trial participants by propensity score. Propensity score matching was applied to control for key clinicopathologic factors, enabling comparison of trial and non-trial patients who were otherwise comparable on observed characteristics. Two matched non-trial cohorts — one contemporary with the trial period and one drawn from before the trial began — served as comparators.
What Was Observed
- Trial patients had substantially higher two-year treatment-free survival than their matched real-world counterparts: 84% of G-MINOR patients remained free of secondary treatment at two years versus 74% in the contemporary MUSIC cohort (p < 0.001), a difference representing meaningfully less treatment activity in the trial setting.
- The absolute number of patients receiving secondary treatment was strikingly different across groups. Within G-MINOR, 69 of 338 patients received secondary treatment (31 adjuvant, 38 salvage); in the contemporary MUSIC cohort, 266 of 1,014 received treatment (183 adjuvant, 83 salvage); and in the pre-trial MUSIC cohort, 104 of 338 did (60 adjuvant, 44 salvage). These differences indicate that trial-enrolled patients were far less likely to proceed to secondary treatment regardless of the comparison group used.
- Time to secondary treatment was consistently and significantly shorter among non-trial MUSIC patients across all comparisons, meaning real-world patients moved to adjuvant or salvage therapy more quickly than those in the G-MINOR trial. This pattern held even after stratifying by genomic risk classification, suggesting that the management differences were not simply a reflection of differing underlying disease risk.
Why This Matters
The standard explanation for why RCT results sometimes fail to translate into real-world settings focuses on whether trial participants are representative of the broader patient population. This study challenges that assumption by demonstrating that even patients carefully matched on clinicopathologic factors were managed differently depending on whether they were inside or outside the trial. The authors propose that these management differences — rather than patient selection alone — may account for the divergent outcomes commonly observed between RCTs and real-world practice, which has direct implications for how trial findings are interpreted and applied to routine clinical settings.
How to Read This Result
While propensity score matching controls for measured confounders, this medium-quality observational comparison cannot fully exclude unmeasured differences — such as physician behavior, institutional trial protocols, or patient preferences — that may have contributed to management variation independently of trial enrollment status.
Limitations
The study does not enumerate explicit limitations in the abstract, but residual confounding is a meaningful concern: propensity matching addresses observed variables only, and unmeasured factors such as physician decision-making style, heightened monitoring under trial conditions, or patient awareness of enrollment may have influenced management patterns in ways that cannot be fully separated from the effect of trial participation itself.