Introduction: Treatment on a clinical trial is considered to be beneficial to oncology patients. However, supportive evidence for this is scarce. Trial effect describes the phenomenon of improved health outcomes in patients treated with standard of care (SOC) on trial compared to those receiving SOC outside of a clinical trial. We evaluated trial effect in patients with ovarian cancer treated at our tertiary cancer centre.
Methods: We performed a retrospective cohort study of patients with ovarian cancer treated at The Christie National Health Service Foundation Trust. Patients treated on one of three first-line clinical trials: (SCOTROC-4, ICON-5, ICON-7) were matched (for age, International Federation of Gynaecology and Obstetrics stage, surgical status and performance status) with individuals receiving the same SOC off trial. Survival was calculated using Kaplan-Meier methodology.
Results: 60 patients were evaluated; 30 on trial and 30 on SOC off trial. The median progression-free survival (PFS) was 21.8 months (control group) and 25.9 months (trial group), median overall survival (OS) was 64.3 months (control group) and 68.9 months (trial group). There was no difference in PFS (log-rank test: HR 0.87 (95% CI 0.48 to 1.54), p=0.6) or OS (log-rank test: HR 0.87 (95% CI 0.46 to 1.64), p=0.7) between groups.
Conclusions: Patient survival was similar regardless if treated on trial or as SOC. Our findings do not support trial effect, at least in a tertiary cancer centre. Clinical trial participation in specialised cancer centres promotes best practice to the benefit of all patients. These findings may impact discussions round consent of patients to trials and organisation of oncology services.
Keywords: outcome; ovarian cancer; trial effect.