Is there a positive effect of participation on a clinical trial for patients with advanced non-small cell lung cancer?

Background: There is general belief that patients who enrolled on a clinical trial have better outcomes compared to those who are treated outside of a trial. We analyzed if there was a ′trial effect′ for patients with advanced non-small cell lung cancer (NSCLC) treated with chemotherapy.
Materials and methods: A retrospective analysis of cohorts of patients with advanced NSCLC who received chemotherapy inside and outside of a clinical trial were analyzed for response rates (RR), progression free survival (PFS), overall survival (OS), 1 and 2 year survival.
Results: There were 194 patients who received chemotherapy of which, 54 were on a clinical trial and 140 outside of it. For the whole group, the RR, median PFS, OS, one and two-year survivals were 35.4%, six months (range, 2-70), seven months (range, 2-72), 29.8% and 9.7% respectively. The differences in RR and PFS of patients who were treated inside and outside of a clinical trial were not significant (P=0.6164, 0.0881). The differences in median OS and one-year survivals between the groups were significant (P=0.0052, 0.022). For the whole group, patients who received II line chemotherapy had better OS (P£0.0001). More patients in the trial group received II line chemotherapy (P=0.0004).The difference in the median OS between the groups continued to be significant even after patients who received II line chemotherapy were censored (P=0.0437).
Conclusion: Patients with advanced NSCLC who were treated inside of a clinical trial had better OS compared to those who were treated outside of it.

Keywords
Chemotherapy, experimental arm effect, lung cancer, survival, trial effect