Trial Participation is Not Associated with Better Biochemical Recurrence-free Survival in a Large Cohort of External Beam Radiotherapy-Treated Intermediate- and High-Risk Prostate Cancer Patients.

There is a widespread belief that outcomes of cancer patients treated within clinical trials might not be representative of the outcomes obtained within standard clinical settings. We sought to investigate the effect of trial participation on biochemical recurrence (BCR) in localised, D'Amico intermediate- and high-risk prostate cancer patients treated with external beam radiotherapy (EBRT).

We relied on a study population treated with EBRT between January 2001 and January 2021 at a single tertiary care centre, stratified according to trial enrolment. Separate Kaplan-Meier and multivariable Cox regression models tested BCR-free survival at 60 months within intermediate- and high-risk EBRT patients, after adjustment for covariables. Additionally, the analyses were refitted after inverse probability treatment weighting was performed separately for both risk subgroups.

Of 932 eligible patients, 635 (68%) and 297 (32%) had intermediate- and high-risk prostate cancer, respectively. Overall, 53% of patients were trial participants. BCR rates were 11 versus 5% (P = 0.27) and 12 versus 14% (P = 0.08) in trial participants versus non-participants for intermediate- and high-risk subgroups, respectively. Differences in patient and clinical characteristics were recorded. Trial participation status failed to reach predictor status in multivariable Cox regression models for BCR in both intermediate-risk (hazard ratio 1.34; 95% confidence interval 0.71-2.49; P = 0.4) and high-risk patients (hazard ratio 1.03; 95% confidence interval 0.45-2.34; P = 0.9). Virtually the same results were recorded in inverse probability treatment weighting cohorts.

Relying on a large cohort of EBRT-treated intermediate- and high-risk patients, no BCR differences were recorded between trial participants and non-participants after accounting for confounders.

Clinical oncology (Royal College of Radiologists (Great Britain)). 2022 Sep 14 [Epub ahead of print]

R S Flammia, D Lavigne, Z Tian, F Saad, U Anceschi, M Gallucci, C Leonardo, F Preisser, P Mandel, F K H Chun, P I Karakiewicz, G Delouya, D Taussky, B Hoeh

Department of Maternal-Child and Urological Sciences, Sapienza Rome University, Policlinico Umberto I Hospital, Rome, Italy; Cancer Prognostics and Health Outcomes Unit, Division of Urology, Centre Hospitalier de l'Université de Montréal (CHUM), Montréal, Québec, Canada., Department of Radiation Oncology, Centre Hospitalier de l'Université de Montréal (CHUM), Montréal, Québec, Canada. Electronic address: ., Cancer Prognostics and Health Outcomes Unit, Division of Urology, Centre Hospitalier de l'Université de Montréal (CHUM), Montréal, Québec, Canada., Cancer Prognostics and Health Outcomes Unit, Division of Urology, Centre Hospitalier de l'Université de Montréal (CHUM), Montréal, Québec, Canada; Department of Surgery, Division of Urology, Centre Hospitalier de l'Université de Montréal (CHUM), Montréal, Québec, Canada., Department of Maternal-Child and Urological Sciences, Sapienza Rome University, Policlinico Umberto I Hospital, Rome, Italy; Department of Uro-oncology, National Cancer Institute, IRCCS "IFO-Reginal Elena", Rome, Italy., Department of Maternal-Child and Urological Sciences, Sapienza Rome University, Policlinico Umberto I Hospital, Rome, Italy., Department of Urology, University Hospital Frankfurt, Goethe University Frankfurt am Main, Frankfurt am Main, Germany., Department of Radiation Oncology, Centre Hospitalier de l'Université de Montréal (CHUM), Montréal, Québec, Canada., Cancer Prognostics and Health Outcomes Unit, Division of Urology, Centre Hospitalier de l'Université de Montréal (CHUM), Montréal, Québec, Canada; Department of Urology, University Hospital Frankfurt, Goethe University Frankfurt am Main, Frankfurt am Main, Germany.

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