Comparison of outcomes of radiotherapy-treated localized prostate cancer patients within a clinical trial setting versus real-life setting.

AIM: To assess whether clinical trial participation affects survival outcomes of radiotherapy-treated localized prostate cancer patients compared with similar treatment within a real-world setting.

METHODS: This is a comparative analysis of the outcomes of localized prostate cancer patients treated within two clinical trials (NCT00331773; NCT00004054) versus the outcomes of similar cohorts of patients registered within the SEER database and treated with radiotherapy. Propensity score matching was conducted to account for heterogeneity in background patient information. Within the postmatching cohort, Kaplan-Meier survival according to treatment setting was reconducted. Moreover, an assessment of the impact of treatment setting on overall survival (OS) was conducted in a multivariate Cox regression model adjusted for age, race, ethnicity, T-stage, PSA and Gleason score.

RESULTS: A total of 5209 low-risk patients and 2115 high-risk patients were included in the current analysis. For both low- and high-risk disease, Kaplan-Meier analysis for OS in the postmatching cohort did not show any difference in OS between patients treated within clinical trial setting versus patients treated within SEER database (p = 0.176; p = 0.097; respectively). Likewise in multivariate Cox regression analysis, treatment context (clinical trial vs SEER) does not affect OS for either low- or high-risk disease (p = 0.470; p = 0.412; respectively).

CONCLUSION: After accounting for possible confounders in baseline characteristics, there was no conclusive evidence of a survival difference between localized prostate cancer patients treated with external beam radiotherapy within routine, real-world settings compared with patients treated within clinical trials.